diff --git a/appveyor.yml b/appveyor.yml
index f5911540..4f9fd582 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -18,11 +18,8 @@ init:
 - call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"
 
 install:
-    - build_win
-    - build_win test
     - choco install nsis -y -pre
-    - build_win dist
-    
+    - build_win all
 build: off
 
 only_commits:
@@ -31,7 +28,7 @@ only_commits:
     - src/
 
 artifacts:
-    - path: janet-installer.exe
+    - path: janet-v1.2.0-windows-installer.exe
       name: janet-v1.2.0-windows-installer.exe
       type: File
 
diff --git a/auxlib/cook.janet b/auxlib/cook.janet
index 5ff11b70..09d08711 100644
--- a/auxlib/cook.janet
+++ b/auxlib/cook.janet
@@ -113,7 +113,7 @@
 
 (def default-compiler (if is-win "cl" "cc"))
 (def default-linker (if is-win "link" "cc"))
-(def default-archiver (if is-win "link" "ar"))
+(def default-archiver (if is-win "lib" "ar"))
 
 # Default flags for natives, but not required
 (def default-lflags (if is-win ["/nologo"] []))
@@ -277,7 +277,7 @@
     (error "cannot find libpath: provide --libpath or JANET_LIBPATH"))
   (string (dyn :libpath JANET_LIBPATH)
           sep
-          "libjanet.a"))
+          (if is-win "libjanet.lib" "libjanet.a")))
 
 (defn- win-import-library
   "On windows, an import library is needed to link to a dll statically."
@@ -314,7 +314,7 @@
   (rule target objects
         (print "creating static library " target "...")
         (if is-win
-          (shell ar "/lib" "/nologo" (string "/out:" target) ;objects)
+          (shell ar "/nologo" (string "/out:" target) ;objects)
           (shell ar "rcs" target ;objects))))
 
 (defn- create-buffer-c-impl
@@ -456,9 +456,9 @@ int main(int argc, const char **argv) {
     (try (rm path) ([err]
                     (unless (= err "No such file or directory")
                       (error err)))))
+  (:close f)
   (print "removing " manifest)
   (rm manifest)
-  (:close f)
   (print "Uninstalled."))
 
 (defn clear-cache
diff --git a/build_win.bat b/build_win.bat
index 14dd1961..e8d41c29 100644
--- a/build_win.bat
+++ b/build_win.bat
@@ -14,10 +14,12 @@
 @if "%1"=="test" goto TEST
 @if "%1"=="dist" goto DIST
 @if "%1"=="install" goto INSTALL
+@if "%1"=="test-install" goto TESTINSTALL
+@if "%1"=="all" goto ALL
 
 @rem Set compile and link options here
 @setlocal
-@set JANET_COMPILE=cl /nologo /Isrc\include /Isrc\conf /c /O2 /W3 /LD /D_CRT_SECURE_NO_WARNINGS
+@set JANET_COMPILE=cl /nologo /Isrc\include /Isrc\conf /c /O2 /W3 /D_CRT_SECURE_NO_WARNINGS
 @set JANET_LINK=link /nologo
 @set JANET_LINK_STATIC=lib /nologo
 
@@ -81,12 +83,8 @@ for %%f in (src\mainclient\*.c) do (
 @if errorlevel 1 goto :BUILDFAIL
 
 @rem Build static library (libjanet.a)
-@rem %JANET_LINK_STATIC% /out:build\libjanet.a build\core\*.obj build\core_image.obj
-@rem @if errorlevel 1 goto :BUILDFAIL
-
-@rem Build dynamic library (janet.dll)
-@rem %JANET_LINK% /out:build\janet.dll /dll build\core\*.obj build\core_image.obj
-@rem @if errorlevel 1 goto :BUILDFAIL
+%JANET_LINK_STATIC% /out:build\libjanet.lib build\core\*.obj build\core_image.obj
+@if errorlevel 1 goto :BUILDFAIL
 
 @rem Gen amlag
 setlocal enabledelayedexpansion
@@ -94,7 +92,7 @@ set "amalg_files="
 for %%f in (src\core\*.c) do (
     set "amalg_files=!amalg_files! %%f"
 )
-build\janet.exe tools\amalg.janet src\core\util.h src\core\state.h src\core\gc.h src\core\vector.h src\core\fiber.h src\core\regalloc.h src\core\compile.h src\core\emit.h src\core\symcache.h %amalg_files% build\core_image.c > build\janet.c
+janet.exe tools\amalg.janet src\core\util.h src\core\state.h src\core\gc.h src\core\vector.h src\core\fiber.h src\core\regalloc.h src\core\compile.h src\core\emit.h src\core\symcache.h %amalg_files% build\core_image.c > build\janet.c
 
 echo === Successfully built janet.exe for Windows ===
 echo === Run 'build_win test' to run tests. ==
@@ -126,7 +124,7 @@ exit /b 0
 :TEST
 for %%f in (test/suite*.janet) do (
     janet.exe test\%%f
-    @if errorlevel 1 goto :TESTFAIL
+    @if errorlevel 1 goto TESTFAIL
 )
 exit /b 0
 
@@ -145,9 +143,7 @@ copy janet.exp dist\janet.exp
 
 copy src\include\janet.h dist\janet.h
 copy src\conf\janetconf.h dist\janetconf.h
-
-@rem copy build\janet.dll dist\janet.dll
-@rem copy build\libjanet.a dist\libjanet.a
+copy build\libjanet.lib dist\libjanet.lib
 
 copy auxlib\cook.janet dist\cook.janet
 copy auxlib\path.janet dist\path.janet
@@ -159,13 +155,39 @@ copy tools\jpm.bat dist\jpm.bat
 "C:\Program Files (x86)\NSIS\makensis.exe" janet-installer.nsi
 exit /b 0
 
-:INSTALL
 @rem Run the installer. (Installs to the local user with default settings)
+:INSTALL
+@echo Running Installer...
 FOR %%a in (janet-*-windows-installer.exe) DO (
     %%a /S /D=%userprofile%\AppData\Local\Janet\
 )
 exit /b 0
 
+@rem Test the installation.
+:TESTINSTALL
+pushd test\install
+call jpm clean
+@if errorlevel 1 goto :TESTFAIL
+call jpm test
+@if errorlevel 1 goto :TESTFAIL
+popd
+exit /b 0
+
+@rem build, test, dist, install. Useful for local dev.
+:ALL
+call %0 build
+@if errorlevel 1 exit /b 1
+call %0 test
+@if errorlevel 1 exit /b 1
+call %0 dist
+@if errorlevel 1 exit /b 1
+call %0 install
+@if errorlevel 1 exit /b 1
+call %0 test-install
+@if errorlevel 1 exit /b 1
+@echo Done!
+exit /b 0
+
 :TESTFAIL
 @echo.
 @echo *******************************************************
diff --git a/janet-installer.nsi b/janet-installer.nsi
index 17b070ca..2278bb5e 100644
--- a/janet-installer.nsi
+++ b/janet-installer.nsi
@@ -20,6 +20,7 @@ VIFileVersion "${PRODUCT_VERSION}"
 !include "MUI2.nsh"
 !include ".\tools\EnvVarUpdate.nsh"
 !include "LogicLib.nsh"
+!include "./tools\FileAssociation.nsh"
 
 # Basics
 Name "Janet"
@@ -99,8 +100,7 @@ section "Janet" BfWSection
     file /oname=C\janet.lib dist\janet.lib
     file /oname=C\janet.exp dist\janet.exp
     file /oname=C\janet.c dist\janet.c
-    #file /oname=C\janet.dll dist\janet.dll
-    #file /oname=C\libjanet.a dist\libjanet.a
+    file /oname=C\libjanet.lib dist\libjanet.lib
 
     # Documentation
     file /oname=docs\docs.html dist\doc.html
@@ -126,6 +126,9 @@ section "Janet" BfWSection
     # Update path
     ${EnvVarUpdate} $0 "PATH" "A" "HKCU" "$INSTDIR\bin" ; Append
     ${EnvVarUpdate} $0 "PATH" "A" "HKLM" "$INSTDIR\bin" ; Append
+    
+    # File Assocations
+    ${RegisterExtension} "$INSTDIR\bin\janet.exe" ".janet" "Janet Source File"
 
 	# Registry information for add/remove programs
 	WriteRegStr SHCTX "${UNINST_KEY}" "DisplayName" "Janet"
@@ -174,6 +177,9 @@ section "uninstall"
     # Unset PATH
     ${un.EnvVarUpdate} $0 "PATH" "R" "HKCU" "$INSTDIR\bin" ; Remove
     ${un.EnvVarUpdate} $0 "PATH" "R" "HKLM" "$INSTDIR\bin" ; Remove
+    
+    # File Associations
+    ${UnRegisterExtension} ".janet" "Janet Source File"
 
     # make sure windows knows about the change
     SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
diff --git a/src/core/corelib.c b/src/core/corelib.c
index 55a5b8f2..f7faea2e 100644
--- a/src/core/corelib.c
+++ b/src/core/corelib.c
@@ -45,7 +45,14 @@ typedef int Clib;
 typedef HINSTANCE Clib;
 #define load_clib(name) LoadLibrary((name))
 #define symbol_clib(lib, sym) GetProcAddress((lib), (sym))
-#define error_clib() "could not load dynamic library"
+static char error_clib_buf[256];
+static char *error_clib(void) {
+    FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+               NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 
+               error_clib_buf, sizeof(error_clib_buf), NULL);
+    error_clib_buf[strlen(error_clib_buf) - 1] = '\0';
+    return error_clib_buf;
+}
 #else
 #include <dlfcn.h>
 typedef void *Clib;
diff --git a/src/mainclient/main.c b/src/mainclient/main.c
index baed5a79..dd862eb4 100644
--- a/src/mainclient/main.c
+++ b/src/mainclient/main.c
@@ -25,6 +25,7 @@
 
 #ifdef _WIN32
 #include <windows.h>
+#include <shlwapi.h>
 #ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
 #define ENABLE_VIRTUAL_TERMINAL_PROCESSING 0x0004
 #endif
@@ -38,14 +39,33 @@ int main(int argc, char **argv) {
     JanetArray *args;
     JanetTable *env;
 
-    /* Enable color console on windows 10 console and utf8 output. */
 #ifdef _WIN32
+    /* Enable color console on windows 10 console and utf8 output. */
     HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
     DWORD dwMode = 0;
     GetConsoleMode(hOut, &dwMode);
     dwMode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING;
     SetConsoleMode(hOut, dwMode);
     SetConsoleOutputCP(65001);
+    
+    /* Add directory containing janet.exe as DLL search path for
+    dynamic modules on windows. This is needed because dynamic modules reference
+    janet.exe for symbols. Otherwise, janet.exe would have to be in the current directory
+    to load natives correctly. */
+ #ifndef JANET_NO_DYNAMIC_MODULES
+    {
+        SetDefaultDllDirectories(LOAD_LIBRARY_SEARCH_USER_DIRS);
+        HMODULE hModule = GetModuleHandleW(NULL);
+        wchar_t path[MAX_PATH];
+        GetModuleFileNameW(hModule, path, MAX_PATH);
+        size_t i = wcsnlen(path, MAX_PATH);
+        while (i > 0 && path[i] != '\\')
+            path[i--] = '\0';
+        if (i) AddDllDirectory(path);
+        GetCurrentDirectoryW(MAX_PATH, path);
+        AddDllDirectory(path);
+    }
+#endif
 #endif
 
     /* Set up VM */
@@ -67,7 +87,7 @@ int main(int argc, char **argv) {
 
     /* Save current executable path to (dyn :executable) */
     janet_table_put(env, janet_ckeywordv("executable"), janet_cstringv(argv[0]));
-
+    
     /* Run startup script */
     status = janet_dobytes(env, janet_gen_init, janet_gen_init_size, "init.janet", NULL);
 
diff --git a/tools/FileAssociation.nsh b/tools/FileAssociation.nsh
new file mode 100644
index 00000000..71a9162e
--- /dev/null
+++ b/tools/FileAssociation.nsh
@@ -0,0 +1,190 @@
+/*
+_____________________________________________________________________________
+ 
+                       File Association
+_____________________________________________________________________________
+ 
+ Based on code taken from http://nsis.sourceforge.net/File_Association 
+ 
+ Usage in script:
+ 1. !include "FileAssociation.nsh"
+ 2. [Section|Function]
+      ${FileAssociationFunction} "Param1" "Param2" "..." $var
+    [SectionEnd|FunctionEnd]
+ 
+ FileAssociationFunction=[RegisterExtension|UnRegisterExtension]
+ 
+_____________________________________________________________________________
+ 
+ ${RegisterExtension} "[executable]" "[extension]" "[description]"
+ 
+"[executable]"     ; executable which opens the file format
+                   ;
+"[extension]"      ; extension, which represents the file format to open
+                   ;
+"[description]"    ; description for the extension. This will be display in Windows Explorer.
+                   ;
+ 
+ 
+ ${UnRegisterExtension} "[extension]" "[description]"
+ 
+"[extension]"      ; extension, which represents the file format to open
+                   ;
+"[description]"    ; description for the extension. This will be display in Windows Explorer.
+                   ;
+ 
+_____________________________________________________________________________
+ 
+                         Macros
+_____________________________________________________________________________
+ 
+ Change log window verbosity (default: 3=no script)
+ 
+ Example:
+ !include "FileAssociation.nsh"
+ !insertmacro RegisterExtension
+ ${FileAssociation_VERBOSE} 4   # all verbosity
+ !insertmacro UnRegisterExtension
+ ${FileAssociation_VERBOSE} 3   # no script
+*/
+ 
+ 
+!ifndef FileAssociation_INCLUDED
+!define FileAssociation_INCLUDED
+ 
+!include Util.nsh
+ 
+!verbose push
+!verbose 3
+!ifndef _FileAssociation_VERBOSE
+  !define _FileAssociation_VERBOSE 3
+!endif
+!verbose ${_FileAssociation_VERBOSE}
+!define FileAssociation_VERBOSE `!insertmacro FileAssociation_VERBOSE`
+!verbose pop
+ 
+!macro FileAssociation_VERBOSE _VERBOSE
+  !verbose push
+  !verbose 3
+  !undef _FileAssociation_VERBOSE
+  !define _FileAssociation_VERBOSE ${_VERBOSE}
+  !verbose pop
+!macroend
+ 
+ 
+ 
+!macro RegisterExtensionCall _EXECUTABLE _EXTENSION _DESCRIPTION
+  !verbose push
+  !verbose ${_FileAssociation_VERBOSE}
+  Push `${_DESCRIPTION}`
+  Push `${_EXTENSION}`
+  Push `${_EXECUTABLE}`
+  ${CallArtificialFunction} RegisterExtension_
+  !verbose pop
+!macroend
+ 
+!macro UnRegisterExtensionCall _EXTENSION _DESCRIPTION
+  !verbose push
+  !verbose ${_FileAssociation_VERBOSE}
+  Push `${_EXTENSION}`
+  Push `${_DESCRIPTION}`
+  ${CallArtificialFunction} UnRegisterExtension_
+  !verbose pop
+!macroend
+ 
+ 
+ 
+!define RegisterExtension `!insertmacro RegisterExtensionCall`
+!define un.RegisterExtension `!insertmacro RegisterExtensionCall`
+ 
+!macro RegisterExtension
+!macroend
+ 
+!macro un.RegisterExtension
+!macroend
+ 
+!macro RegisterExtension_
+  !verbose push
+  !verbose ${_FileAssociation_VERBOSE}
+ 
+  Exch $R2 ;exe
+  Exch
+  Exch $R1 ;ext
+  Exch
+  Exch 2
+  Exch $R0 ;desc
+  Exch 2
+  Push $0
+  Push $1
+ 
+  ReadRegStr $1 HKCR $R1 ""  ; read current file association
+  StrCmp "$1" "" NoBackup  ; is it empty
+  StrCmp "$1" "$R0" NoBackup  ; is it our own
+    WriteRegStr HKCR $R1 "backup_val" "$1"  ; backup current value
+NoBackup:
+  WriteRegStr HKCR $R1 "" "$R0"  ; set our file association
+ 
+  ReadRegStr $0 HKCR $R0 ""
+  StrCmp $0 "" 0 Skip
+    WriteRegStr HKCR "$R0" "" "$R0"
+    WriteRegStr HKCR "$R0\shell" "" "open"
+    WriteRegStr HKCR "$R0\DefaultIcon" "" "$R2,0"
+Skip:
+  WriteRegStr HKCR "$R0\shell\open\command" "" '"$R2" "%1"'
+  WriteRegStr HKCR "$R0\shell\edit" "" "Edit $R0"
+  WriteRegStr HKCR "$R0\shell\edit\command" "" '"$R2" "%1"'
+ 
+  Pop $1
+  Pop $0
+  Pop $R2
+  Pop $R1
+  Pop $R0
+ 
+  !verbose pop
+!macroend
+ 
+ 
+ 
+!define UnRegisterExtension `!insertmacro UnRegisterExtensionCall`
+!define un.UnRegisterExtension `!insertmacro UnRegisterExtensionCall`
+ 
+!macro UnRegisterExtension
+!macroend
+ 
+!macro un.UnRegisterExtension
+!macroend
+ 
+!macro UnRegisterExtension_
+  !verbose push
+  !verbose ${_FileAssociation_VERBOSE}
+ 
+  Exch $R1 ;desc
+  Exch
+  Exch $R0 ;ext
+  Exch
+  Push $0
+  Push $1
+ 
+  ReadRegStr $1 HKCR $R0 ""
+  StrCmp $1 $R1 0 NoOwn ; only do this if we own it
+  ReadRegStr $1 HKCR $R0 "backup_val"
+  StrCmp $1 "" 0 Restore ; if backup="" then delete the whole key
+  DeleteRegKey HKCR $R0
+  Goto NoOwn
+ 
+Restore:
+  WriteRegStr HKCR $R0 "" $1
+  DeleteRegValue HKCR $R0 "backup_val"
+  DeleteRegKey HKCR $R1 ;Delete key with association name settings
+ 
+NoOwn:
+ 
+  Pop $1
+  Pop $0
+  Pop $R1
+  Pop $R0
+ 
+  !verbose pop
+!macroend
+ 
+!endif # !FileAssociation_INCLUDED