|I trust you are familiar with the registry, otherwise you could cause damage requiring a system reload.|
If you are going to start working in the registry, first download ERUNT (feee) which can save your registry before you start. See this website:
If things go wrong it can then restore the previous registry unchanged. This is better than using the export & import facility in the registry because that only "merges" the saved registry back with whatever has already been altered.
Note that I do not agree with the suggestion on the ERUNT website (FAQ's) that you should turn off System Restore. Although often restoring a previously saved good registry can fix a problem more quickly and reliably than System Restore, it is NOT a replacement. They are two quite different facilities.
Always pop back and let us know the outcome - thanks