Malwarebytes is a free downloadable program that I use in conjunction with AVG, as it seems to catch some things that AVG doesn't.
That said, I had to keep trying, and then google every error message I got, to find all the little pieces of the virus and the appropriate ways to remove them. It had found a way to repopulate itself and redirect me online so I couldn't upgrade AVG. It took days, but I did it.
Sending good thoughts your way!