Use registry cleaners if you know what you are doing. I disagree with the guys who are one sided and say you don't absolutely need to use a registry cleaner on Windows 7. I say you do need them but stay away if you don't know where the keys found lead to. They can help you remove remnants or malware and remove applications.
If you have a system with 1 GB or below amount of RAM, the performance does degrade noticeably after some time and using a registry cleaner will improve that a but but destroy a few things if you remove something really needed.
Those dead keys that lead to entries of uninstalled programs are relatively safe to delete but those that you don't know, better leave them be and always reserve a backup such as a restore point or use a program called Erunt to backup the whole registry before any cleaning.
If you have any questions about registry cleaners, always use the search function so that you can see the dozens of threads that talk about it and from there, maybe you can weigh the pros and cons and decide for yourself if you need a registry cleaner.
Iobit System Care is a fair program, but if I was an inexperienced user, I would not use its registry cleaner and system optimization tools but the tools besides those are safe.
CCleaner is a light registry cleaner. Its relatively safer than many other registry cleaning tools out there but even that has caused problems.
I then did the research I should have done before hand and learned.
