All kind of problems with AVG

Hi!
For some time ago, my AVG free version got an error while running. It worked about halfway, before I got a message about troubles. I'd now tried to repair it, wich didn't work and neither could I uninstall it. Also tried to download a new one, but it couldn't install, probably because of the other I have on my PC. I have no idea what to do! Before this happened it worked perfeclty fine. Had some troubles on my PC since I by mistake downloaded a program called Spyhunter. It's impossible to get rid of! When trying, my computer crashes. The AVG-trouble did not occur at the same time as I got Spyhunter though, it happened later. Thanks in advance/Denise Lundberg