Scott Hanselman has a great suggestion. This holiday weekend (assuming you’re in the U.S., that is), take a few minutes to clean up PCs that belong to your friends and relatives. (With their permission, of course!) His checklist is a good start:
This holiday weekend, when you (computer person) visit your cousin/dad/aunt/grandma, give them a gift:
- install anti-spyware software and configure it to run automatically on startup. I use SpyBot Search and Destroy.
- enable their existing Windows Xp firewall, just turn it on
- give them anti-Virus software (or install the free version of AVG)
- run diskcleanup and defrag
- lower the size of the IE cache
- turn the security in IE up (for ActiveX controls) or install FireFox.
Great idea! I would add:
- Get the latest patches from Windows Update and turn on Automatic Updates.
The whole process shouldn’t take more than 30 minutes, especially if you download Service Packs and anti-virus/spyware tools to your computer first and burn them to a CD.
Ed Bott 
Great suggestions Ed. Here are a couple more:
Grab the utilities from Gibson Research Corporation (http://www.grc.com) that disable unnecessary Windows services (like Uinversal Plug ‘n Play and Windows Messenger service). They’re free, they’re tiny, and they address potentially big holes in a properly constructed layered defense.
Once you have everything installed, go back to GRC and run a free Shields Up! scan to see how well protected the PC actually is.
Doh! Automatic Updates! I knew I missed one!