Free software!
If you want to protect your PC without going broke, here's a few good links to free software!
WebAttack.com
Home PC Firewall guide
Antivirus
AntiVir Guard Personal Edition - good, and free for personal use, and it works!
Anti-spyware
Ad-aware - detects and removes spyware from your PC
Firewall
Kerio Personal Firewall - free for personal use
Pop-up stopper
PopNot - shareware (try for 30 days) - maybe the best PopUp stopper you can get
Free Surfer mk II - free and almost as good as PopNot?
Google Toolbar - extra toolbar with search box for Google, and pop-up stopper!
Spam killers
MailWasher - detects, deletes, reports and bounces spam...