Built in registry checker

This is what you are looking for and the safest. However, if you are already having issues,, any reg cleaner, even this one can cause more problems, but, that's why you are running it anyway. So, use with caution always. But this is the only one I would recommend.

Windows Live OneCare Clean Up Scanner

I have seen many posts, that start off, I have a problem, since I used a reg cleaner. Just maintain your computer properly. If you are not sure how it is done, just ask. Many of the members will be very happy to give you information.

reg cleaner isn't recommended but in case if you want to use one ,CCcleaner

kucing13 said:

reg cleaner isn't recommended but in case if you want to use one ,CCcleaner

I believe there is an option to use without the reg cleaning.

My advice for the average computer user is DO NOT using a registry cleaner. If you do not have knowledge of the registry, then you are far better off leaving it alone, and definitely not placing blind trust in a program to do the job for you.
Win 7 does not need a registry cleaner. Forget all the "wisdom" you learned about XP. Win 7 is not XP and does not manage the registry the same as XP.

Win 7 is much more efficient at managing the registry than previous Windows versions. If you are very knowledgeable of the registry, you can use Ccleaner to delete keys left over when uninstalling programs. However, these few keys will not make 1 millisecond's difference in performance. If you run Ccleaner or any other registry cleaner and do not know precisely what you are doing, you will have problems down the road. There are no gains to be had from using a registry cleaner and the risk is great.

Well said Carl,as long as you have the option to avoid using reg cleaner. AVOID IT!!