diff --git a/Docs/src/usefulfunc.but b/Docs/src/usefulfunc.but
index bbdf4f1f..9ffa6068 100644
--- a/Docs/src/usefulfunc.but
+++ b/Docs/src/usefulfunc.but
@@ -261,6 +261,66 @@
 \c    Exch $R0
 \c  FunctionEnd
 
+\H{detect.netframework} Is .NET Framework installed?
+
+\c  ; IsDotNETInstalled
+\c  ;
+\c  ; Usage:
+\c  ;   Call IsDotNETInstalled
+\c  ;   Pop $0
+\c  ;   StrCmp $0 1 found.NETFramework no.NETFramework
+\c  
+\c  Function IsDotNETInstalled
+\c    Push $0
+\c    Push $1
+\c    Push $2
+\c    Push $3
+\c    Push $4
+\c  
+\c    ReadRegStr $4 HKEY_LOCAL_MACHINE \
+\c      "Software\Microsoft\.NETFramework" "InstallRoot"
+\c    # remove trailing back slash
+\c    Push $4
+\c    Exch $EXEDIR
+\c    Exch $EXEDIR
+\c    Pop $4
+\c    # if the root directory doesn't exist .NET is not installed
+\c    IfFileExists $4 0 noDotNET
+\c  
+\c    StrCpy $0 0
+\c  
+\c    EnumStart:
+\c  
+\c      EnumRegKey $2 HKEY_LOCAL_MACHINE \
+\c        "Software\Microsoft\.NETFramework\Policy"  $0
+\c      IntOp $0 $0 + 1
+\c      StrCmp $2 "" noDotNET
+\c  
+\c      StrCpy $1 0
+\c  
+\c      EnumPolicy:
+\c  
+\c        EnumRegValue $3 HKEY_LOCAL_MACHINE \
+\c          "Software\Microsoft\.NETFramework\Policy\$2" $1
+\c        IntOp $1 $1 + 1
+\c         StrCmp $3 "" EnumStart
+\c          IfFileExists "$4\$2.$3" foundDotNET EnumPolicy
+\c  
+\c    noDotNET:
+\c      StrCpy $0 0
+\c      Goto done
+\c  
+\c    foundDotNET:
+\c      StrCpy $0 1
+\c  
+\c    done:
+\c      Pop $4
+\c      Pop $3
+\c      Pop $2
+\c      Pop $1
+\c      Exch $0
+\c  FunctionEnd
+
 \H{isflashinstalled} Is Macromedia Flash Player installed?
 
 \c  ; IsFlashInstalled