diff --git a/mkvtoolnix.nsi b/mkvtoolnix.nsi
index c36c681eb..75967cbd5 100644
--- a/mkvtoolnix.nsi
+++ b/mkvtoolnix.nsi
@@ -65,6 +65,246 @@ InstallDirRegKey HKLM "${PRODUCT_DIR_REGKEY}" ""
 ShowInstDetails show
 ShowUnInstDetails show
 
+; Add something to the PATH environment variable.
+; From http://nsis.sourceforge.net/archive/viewpage.php?pageid=91
+
+!verbose 3
+!include "WinMessages.NSH"
+!verbose 4
+
+; AddToPath - Adds the given dir to the search path.
+;        Input - head of the stack
+;        Note - Win9x systems requires reboot
+
+Function AddToPath
+  Exch $0
+  Push $1
+  Push $2
+  Push $3
+
+  # don't add if the path doesn't exist
+  IfFileExists $0 "" AddToPath_done
+
+  ReadEnvStr $1 PATH
+  Push "$1;"
+  Push "$0;"
+  Call StrStr
+  Pop $2
+  StrCmp $2 "" "" AddToPath_done
+  Push "$1;"
+  Push "$0\;"
+  Call StrStr
+  Pop $2
+  StrCmp $2 "" "" AddToPath_done
+  GetFullPathName /SHORT $3 $0
+  Push "$1;"
+  Push "$3;"
+  Call StrStr
+  Pop $2
+  StrCmp $2 "" "" AddToPath_done
+  Push "$1;"
+  Push "$3\;"
+  Call StrStr
+  Pop $2
+  StrCmp $2 "" "" AddToPath_done
+
+  Call IsNT
+  Pop $1
+  StrCmp $1 1 AddToPath_NT
+    ; Not on NT
+    StrCpy $1 $WINDIR 2
+    FileOpen $1 "$1\autoexec.bat" a
+    FileSeek $1 -1 END
+    FileReadByte $1 $2
+    IntCmp $2 26 0 +2 +2 # DOS EOF
+      FileSeek $1 -1 END # write over EOF
+    FileWrite $1 "$\r$\nSET PATH=%PATH%;$3$\r$\n"
+    FileClose $1
+    SetRebootFlag true
+    Goto AddToPath_done
+
+  AddToPath_NT:
+    ReadRegStr $1 HKCU "Environment" "PATH"
+    StrCpy $2 $1 1 -1 # copy last char
+    StrCmp $2 ";" 0 +2 # if last char == ;
+      StrCpy $1 $1 -1 # remove last char
+    StrCmp $1 "" AddToPath_NTdoIt
+      StrCpy $0 "$1;$0"
+    AddToPath_NTdoIt:
+      WriteRegExpandStr HKCU "Environment" "PATH" $0
+      SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
+
+  AddToPath_done:
+    Pop $3
+    Pop $2
+    Pop $1
+    Pop $0
+FunctionEnd
+
+; RemoveFromPath - Remove a given dir from the path
+;     Input: head of the stack
+
+Function un.RemoveFromPath
+  Exch $0
+  Push $1
+  Push $2
+  Push $3
+  Push $4
+  Push $5
+  Push $6
+
+  IntFmt $6 "%c" 26 # DOS EOF
+
+  Call un.IsNT
+  Pop $1
+  StrCmp $1 1 unRemoveFromPath_NT
+    ; Not on NT
+    StrCpy $1 $WINDIR 2
+    FileOpen $1 "$1\autoexec.bat" r
+    GetTempFileName $4
+    FileOpen $2 $4 w
+    GetFullPathName /SHORT $0 $0
+    StrCpy $0 "SET PATH=%PATH%;$0"
+    Goto unRemoveFromPath_dosLoop
+
+    unRemoveFromPath_dosLoop:
+      FileRead $1 $3
+      StrCpy $5 $3 1 -1 # read last char
+      StrCmp $5 $6 0 +2 # if DOS EOF
+        StrCpy $3 $3 -1 # remove DOS EOF so we can compare
+      StrCmp $3 "$0$\r$\n" unRemoveFromPath_dosLoopRemoveLine
+      StrCmp $3 "$0$\n" unRemoveFromPath_dosLoopRemoveLine
+      StrCmp $3 "$0" unRemoveFromPath_dosLoopRemoveLine
+      StrCmp $3 "" unRemoveFromPath_dosLoopEnd
+      FileWrite $2 $3
+      Goto unRemoveFromPath_dosLoop
+      unRemoveFromPath_dosLoopRemoveLine:
+        SetRebootFlag true
+        Goto unRemoveFromPath_dosLoop
+
+    unRemoveFromPath_dosLoopEnd:
+      FileClose $2
+      FileClose $1
+      StrCpy $1 $WINDIR 2
+      Delete "$1\autoexec.bat"
+      CopyFiles /SILENT $4 "$1\autoexec.bat"
+      Delete $4
+      Goto unRemoveFromPath_done
+
+  unRemoveFromPath_NT:
+    ReadRegStr $1 HKCU "Environment" "PATH"
+    StrCpy $5 $1 1 -1 # copy last char
+    StrCmp $5 ";" +2 # if last char != ;
+      StrCpy $1 "$1;" # append ;
+    Push $1
+    Push "$0;"
+    Call un.StrStr ; Find `$0;` in $1
+    Pop $2 ; pos of our dir
+    StrCmp $2 "" unRemoveFromPath_done
+      ; else, it is in path
+      # $0 - path to add
+      # $1 - path var
+      StrLen $3 "$0;"
+      StrLen $4 $2
+      StrCpy $5 $1 -$4 # $5 is now the part before the path to remove
+      StrCpy $6 $2 "" $3 # $6 is now the part after the path to remove
+      StrCpy $3 $5$6
+
+      StrCpy $5 $3 1 -1 # copy last char
+      StrCmp $5 ";" 0 +2 # if last char == ;
+        StrCpy $3 $3 -1 # remove last char
+
+      WriteRegExpandStr HKCU "Environment" "PATH" $3
+      SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
+
+  unRemoveFromPath_done:
+    Pop $6
+    Pop $5
+    Pop $4
+    Pop $3
+    Pop $2
+    Pop $1
+    Pop $0
+FunctionEnd
+
+###########################################
+#            Utility Functions            #
+###########################################
+
+; IsNT
+; no input
+; output, top of the stack = 1 if NT or 0 if not
+;
+; Usage:
+;   Call IsNT
+;   Pop $R0
+;  ($R0 at this point is 1 or 0)
+
+!macro IsNT un
+Function ${un}IsNT
+  Push $0
+  ReadRegStr $0 HKLM "SOFTWARE\Microsoft\Windows NT\CurrentVersion" CurrentVersion
+  StrCmp $0 "" 0 IsNT_yes
+  ; we are not NT.
+  Pop $0
+  Push 0
+  Return
+
+  IsNT_yes:
+    ; NT!!!
+    Pop $0
+    Push 1
+FunctionEnd
+!macroend
+!insertmacro IsNT ""
+!insertmacro IsNT "un."
+
+; StrStr
+; input, top of stack = string to search for
+;        top of stack-1 = string to search in
+; output, top of stack (replaces with the portion of the string remaining)
+; modifies no other variables.
+;
+; Usage:
+;   Push "this is a long ass string"
+;   Push "ass"
+;   Call StrStr
+;   Pop $R0
+;  ($R0 at this point is "ass string")
+
+!macro StrStr un
+Function ${un}StrStr
+Exch $R1 ; st=haystack,old$R1, $R1=needle
+  Exch    ; st=old$R1,haystack
+  Exch $R2 ; st=old$R1,old$R2, $R2=haystack
+  Push $R3
+  Push $R4
+  Push $R5
+  StrLen $R3 $R1
+  StrCpy $R4 0
+  ; $R1=needle
+  ; $R2=haystack
+  ; $R3=len(needle)
+  ; $R4=cnt
+  ; $R5=tmp
+  loop:
+    StrCpy $R5 $R2 $R3 $R4
+    StrCmp $R5 $R1 done
+    StrCmp $R5 "" done
+    IntOp $R4 $R4 + 1
+    Goto loop
+done:
+  StrCpy $R1 $R2 "" $R4
+  Pop $R5
+  Pop $R4
+  Pop $R3
+  Pop $R2
+  Exch $R1
+FunctionEnd
+!macroend
+!insertmacro StrStr ""
+!insertmacro StrStr "un."
+
 Function .onInit
   !insertmacro MUI_LANGDLL_DISPLAY
 FunctionEnd
@@ -130,6 +370,9 @@ Section -Post
   WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}" "URLInfoAbout" "${PRODUCT_WEB_SITE}"
   WriteRegStr ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}" "Publisher" "${PRODUCT_PUBLISHER}"
   WriteRegStr HKCU "${MTX_REGKEY}\GUI" "installation_path" "$INSTDIR"
+
+  Push $INSTDIR
+  Call AddToPath
 SectionEnd
 
 var unRemoveJobs
@@ -196,6 +439,10 @@ Section Uninstall
   DeleteRegKey ${PRODUCT_UNINST_ROOT_KEY} "${PRODUCT_UNINST_KEY}"
   DeleteRegKey HKLM "${PRODUCT_DIR_REGKEY}"
   DeleteRegKey HKCU "${MTX_REGKEY}"
+
+  Push $INSTDIR
+  Call un.RemoveFromPath
+
   SetAutoClose true
 SectionEnd