Download a copy of Tuneup Utilities 2013, you can run a scan on your computer and it will repair numerous problems in windows and scan the registry, there is also an option that will let you disable programs that are slowing down your computer.

Another good program is Malwarebytes, it scans your system looking for anything that shouldn't be there. Both programs are free to download, just look them up on Google.

I hope this helps, I use them myself, try them out if you find they help you can always buy the full versions.

Harry