System File Checker is a utility in Windows that checks for problems with files on your computer using CMD,
SFC /SCANNOW.
Most people find that they're able to clean their registry with automatic functions or third-party programs. However, you can perform registry cleanup manually using the Windows Registry editor. Unless you are very sure about knowing how to check your registry, I would advise against doing it because you could cause even more problems. Always backup your registry before you start exploring. I use a third party program to check and correct my registry.
