Just a though from a linux geek:
Get a copy of kubuntu on cd, save everything important to the external drive, and install it instead. You can get the install CD free by downloading it, or having it shipped to your house for free as well (ubuntu.com)
The install is easy enough that my wife did her own laptop, just put the cd in the drive and boot the machine. You have to answer about 6 questions (your name, timezone, password, etc..) and it does the standard install with firefox, openoffice and a bunch of other stuff.
If you are planning on wiping the machine, there is not much to lose by trying. And linux doesn't require A/V software or anything like that (much like a mac). It is much quicker, and doesn't require the usual maintenance that windows does at all (spybot/AV/defrag/cleaners). Just use and enjoy.
Disclaimer: I'm a linux sysadmin, running 4,500 linux machines in a public school system. I think if a 6 year old can run it just fine, most people should be OK
