Originally Posted by bacon12
What Vin said would probably work very well. True crypt alone would most likely keep him from accessing any data.
Truecrypt is overkill.
For maximum protection, make sure you set up a truecrypt bootloader so that it boots into the secured partition. Otherwise, if he ever gets physical access again, he could potentially install a rootkit w/ keylogger that would make any encryption pointless- though if he's not very computer savvy, it'd be doubtful he would know how.
Windows is a very insecure OS. Give me physical access to a machine with XP on it, and I'll have admin access within minutes. Even BIOS passwords have limitations
But as long has he's not very computer savvy, just a simple BIOS and password-protected Windows would prevent him from screwing around with the machine.
Don't spend too much money and time to worry about it. At the very most, reformat her HD, and get her a go-phone if she's paranoid.