Just stay away from that 'Avast' thing.. It bogged my computer right down and even though it has a uninstall, it leaves junk threaded all through your system. I thought I finally got it all out, but nope, I still get the odd popup when I try to load an older program.. My Panda virus checker (one year subscription came with the new computer) went south for some reason, so I went to the mcfee site and they have a 3 month. free trial. I used it on an older system and was satified, their current version works very well and will buy it before the trial runs out.. On these free checkers, You 'do' get what you pay for in most cases.