Ok you are halfway there. This is the second step. After I get rid of any Malware I might have then I run the C-Cleaner Registery Cleaner.
Doing these two things, repairing you registry and erasing deep viruses, would make most computers run right if people only knew about it. It is not really a secret but computer repair stores would make a lot less money if more people knew about it.
If you want more choices than Nortons Power Eraser. I really like that one, but there are others at the DCWG website. It never hurts to run two or three of those virus scanners because one will usually find what another missed. Here is the link DCWG.org. Use the choices down under the DNS changer heading. These scanners were made available when the DNS changer virus hit, but we're not looking for a DNS Changer virus. We are looking for a virus that is buried deep like that. Do this and you will see a 98% increase in your computers speed and efficiency.
If you are interested in starting your own website to make some extra money you might be interested in this.