PC World says that one way to keep your data safe is to password protect the hard drive itself.
The article explains how to change password settings in your PC's BIOS to protect the system at a deeper level than Windows allows. After entering the BIOS by pressing the proper key combo at startup (often F1, F2, Delete, or Escape), here are the two settings I think you should zero in on:
Supervisor Password. Enable this password to prevent someone from changing your BIOS settings behind your back. This can allow you to disable booting from a CD, for example, and make sure no one changes that setting to gain access to your PC.
HDD Password. This is the important one. Enable the hard disk password to prevent access to your data even if your hard drive gets installed in another PC. Just don't forget this password, or you'll have to take it to a data recovery service to retrieve your data. Photo by Jeff Kubina