If you are going to mess with registry cleaners (CCleaner), I suggest you create both System Restore points and make backups of your registry before using them.
CCleaner is one of the safer of those type of applications but it can still hose your op system if you do not know what you are doing.
One word of caution with CCleaner:(Modifies registry – Always backup your registry before using)
(Prefetch Cleaning Warning - The Advanced section of Ccleaner has a performance degrading option to “clean Old Prefetch data", never select this option for cleaning as it will actually increase load times for Windows and your installed, most used applications.
Cleaning the Prefetch folder as beneficial is a Myth and actually degrades performance. Windows by default cleans this folder at 128 entries. Anyone who claims this folder should be cleaned for ANY reason does not understand what prefetching is or how it works.)
I suggest Erunt (freeware) to automatically make registry backups on a schedule you set.
ERUNT Emergency Recovery Utility
Registry Backup and Restore for Windows NT/2000/2003/XP http://www.larshederer.homepage.t-online.de/erunt/
Another option other than to use a third party registry cleaner would be to use the following instead:
Windows One Care Free Scan (online scan)
Go to Windows Live Onecare Free Scan
It will say "Get a free PC safety scan"http://safety.live.com/site/en-us/default.htm
Make sure you click "Full Service Scan"
in the middle of the page and not the "Try It Now Free" on the right side.
Allow it to download an Active X component.
Choose "Complete Scan" in the window that opens
Do not click on anything else that offers you a free trial or to sign up if you live in the US.
Allow it to scan - it may take quite a while, maybe two hours or so depending on how big your hard drive is and how fragmented your registry and drive are.
It is made by Microsoft for XP and doesn't have nearly the same propensity to hose your registry that third party aps that alter of change the registry do.