Speaking from personal experience, I recommend NOT using a Reg Cleaner. However if in the end you decide to anyway, I suggest the following.
1. Be sure the one you choose makes a registry backup
of the files it will remove. Note: this backup has nothing to do with the Windows Restore Point.
2. Do not allow it to 'clean' windows system files.
Just a suggestion for you, there is a product (FREE) that is very popular (I use) called CCleaner very user friendly, and hasn't let me down yet, and updates are about every month or so. CCleaner - Update
Best of luck,