Here's a little trick to clean your registry for useless references:
Open a DOS prompt:
The first line will export the registry to a text-file (regfile.txt).Code:
C:\>REGEDIT /E C:\REGFILE.TXT
C:\>REGEDIT /C C:\REGFILE.TXT
The second line restores the registry from that text-file. A nice "side-effect" of this method is that this will screen the programs in regfile.txt to check if they still exist. If they don't, they aren't restored.