[FunkyZero]

There ware ways to secure your computer quite easily.
Built-in encryption on windowsXP is quite strong and as far as I know, it cannot be cracked. I’ve never heard of it being done.
Either use the security options, or consider the computer public domain and modify your usage to suit (ie: don’t store anything on it you consider personal). Use a USB key isntead... most have options built-in for encryption now.

[seemoAR]

I wouldn’t be worried about anything I put on the computer. What is to prevent someone from downloading something illegal to a family computer and accusing someone else?.

[CA Conservative]

Built-in encryption on windowsXP is quite strong and as far as I know, it cannot be cracked.

If you're talking about EFS (encrypting file system), you are both right and wrong. On it's own, EFS uses a strong encryption algorithm, but the weakness is that the key to decrypt the files is the user's account password. Those are stored in the SAM hive on the computer, and unless the user has a strong password, most of those can be quickly cracked using open source tools such as Ophcrack. Once you have the password, EFS becomes useless. I'd recommend a 3rd-party tool such as TrueCrypt, BestCrypt or PGP, with a strong password.