Lifehacker put together two great resources for fixing the computers that your parents/ relatives/ siblings/ uneducated friends have inevitably broken since the last time you were home.
Lifehacker's Thanksgiving PC Rescue Kit (17MB)
Small enough to fit on a flash drive but packed with a bunch of great programs to clean out the junk.
- Ad-Aware - Removes Adware
- ClamWin - Open source antivirus, much less annoying than Norton
- Spybot S&D - Removes Spyware
- Spyware Blaster - Prevents future spyware
- CCleaner - Cleans the cache, temp files, cookies, system logs, startup programs. Definately helps speed things up
Full Walkthrough Complete Step by step to cleaning up the computer. Everything from spyware to firewalls and firefox.