diff --git a/README.md b/README.md
index 9d21e92..7a95ecb 100644
--- a/README.md
+++ b/README.md
@@ -16,8 +16,8 @@ and run it.
 
 Add the installation path to your implementations load path:
 
-    %ProgramFiles%/snow
+    %SNOW_LIBRARY_PATH%
 
 For example with Gauche:
 
-    gosh.exe -r7 -A "%ProgramFiles%/snow" main.scm
+    gosh.exe -r7 -A "%SNOW_LIBRARY_PATH%" main.scm
diff --git a/install.nsi b/install.nsi
index bba4f43..07de8a1 100644
--- a/install.nsi
+++ b/install.nsi
@@ -1,3 +1,5 @@
+
+
 OutFile "setup_snow.exe"
 InstallDir "$PROGRAMFILES64"
 
@@ -6,5 +8,13 @@ Section
     RMDir "$INSTDIR"
     File /r "snow"
     Push "$INSTDIR"
+
+    !include "winmessages.nsh"
+    !define env_hklm 'HKLM "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"'
+    !define env_hkcu 'HKCU "Environment"'
+
+    WriteRegExpandStr ${env_hklm} SNOW_LIBRARY_PATH "$PROGRAMFILES64/snow"
+    WriteRegExpandStr ${env_hkcu} SNOW_LIBRARY_PATH "$PROGRAMFILES64/snow"
+    SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
 SectionEnd