Another tip:
Install a good anti-malware package. Hey this might make a good thread.. What brand of anti-virus-spyware software do you use? Do you use a "suite" of tools? Or pick ala carte?
I use AVG anti-malware package. It has virus and spyware protection. The full blown package also has personal firewall. I don't like personal firewalls so I went with the double play instead of the triple play package.
Then I run adware and spybot every so often. (free versions) This keeps me pretty clean. (which is relative nowadays) That and not clicking links in emails.
Packages that I don't like are Norton which doesn't work worth a darn IMO. Spyware Doctor is OK but I don't like PCTools antivirus. CA makes good stuff (eTrust?)