Seeing you don’t know a lot about computers or your OS.
I would suggest downloading Eusing free registry cleaner.
If you do download Eusing open it click skip --click scan let it run till finished, click repair,
Then scan once more.
You will also see in Eusing Restore Registry if ever needed.

Also you could do a search-- all files & folders for any left over crap you may have.

http://www.snapfiles.com/get/eusingregistry.html

Install Avast & see what happens.