Quote from stevegee58:
Here's some food for thought regarding viruses. I don't use anti-virus software at all! I know that sounds crazy, but there are only very limited ways for viruses to enter your computer. If you avoid these unsafe practices, you'll never get a virus.
The list of biggies:
1) E-mail attachments. Only open an attachment if the e-mail is from a trusted source, and then only if you're expecting an attachment from them. Some attackers send e-mails with forged addresses containing nasties. It can appear from a trusted source but not be.
2) P2P file sharing (Kazaa, LimeWire, Shareaza, FrostWire, etc). It's the wild west out there if you're looking to download illegal music, porn etc from file sharing networks. 95% of the time you'll get what you're looking for. That 5% where you don't can result in disaster. I've had to re-install Windows on my kids' computer twice now because of this.
3) Cracks/keygens. Download and use these at your peril. Just buy the software you're interested in. Don't try to avoid paying for software using cracks and keygens. Maybe half of these things are infected with something nasty.
4) Keep your Windows install up to date. I know everyone hates Microsoft and stuff, but chances are you use it. And the fact is they do have an army of ants constantly plugging holes and exploits in the OS and apps.
If you simply avoid the first 3 things and do the last, you'll never get an infection.
I've met people who claimed that they got a virus spontaneously and were not doing anything questinable. Every time I probed further, it turned out it was due to one of the above list items.
Viruses cannot be "pushed" into your computer, so firewalls don't help. The typical home user has a router (either wireless or not) connected to a cable or DSL modem. By itself, a router gives you all the firewall protection you need. This stops port scanning, etc. Software firewall products are a waste of money. Just buy a router, they're cheap.