Hi andycap84,
What did you use to "clean the registry"? If it was some program like a Registry booster, optimizer, enhancer, cleaner, fixer, repairer or whatever it calls itself, please unintall the program and never use it again. Vista does a fine job on its own of cleaning the registry (despite what scans from these programs may tell you - like you have 6000 errors that need to be repaired or whatever - it's a scam to get you to buy the product). Most such programs do little if any good and some (perhaps many) can cause serious problems. It simply isn't worth the risk - especially when it isn't necessary.
If you went in to regedit.exe and attempted to modify it manually, you should not do that unless you are a professional with special training or following specific instructions by a professional or a microsoft article to resolve some issue. I have a pretty good understanding of the registry and even I don't touch it unless I have no other choice and then I make certain I know exactly what I'm going to do before I even start and am certain it it the correct thing to do (and take precautions as noted below). Do not do so just to "clean it up" - do so only if you have a specific need to do so and understand what you are doing and are under the direction of a professional or following reliable directions provided by Microsoft or a tutorial in this forum or a professional you can trust. Even still, before you start, always create a System Restore point AND a backup of the registry to be on the safe side.
Richard's instructions on System Restore should resolve the problem - but don't rely on that to always get you out of trouble if you ignore the above and use such programs or modify it manually. It usually works, but is not an absolute guarantee and the wrong changes could cause damage even more severe than what you are experiencing (and could disable System Restore) - even to the point of needing to re-install the operating system.
I hope this helps. If not, post back with an explanation of what occurred when you tried System Restore and how exactly you did it.
Good luck!