1)Without a doubt the best Anti Virus protection software is Norton Internet Security but it costs money anything from £32 upwards for a year. And has spin off goodies with it, pop up blocking anti spyware.
2)www.avguk.com its free and its good.
3) http://vil.nai.com/vil/stinger It's one of McFee another good one and free.
4)www.spybot.and also a Programme named Hacker very good anti spyware (see surfing)
5)There are lots of others You pays your money and takes your choice.