(no subject)

I know that I've got a LOT of problems with viruses and spyware on my computer, I was hoping downloading AVG free trial today would help, but when I click on whole computer scan it just cames up like 2 seconds later with "Scan Interrupted. No threats were found". And when I click on fix it comes up with "Could not finish automatic state repair"

I know it's only the free version, but I don't really want to pay for the full version when it hasn't done much to impress me so far that it can clean my computer. Can anyone recommend any effective anti virus programs?