All you need to do is encrypt your sensitive data. The other data, don't encrypt. Don't worry about the BIOS and Windows passwords. Both you can get around.
BIOS - Just take out the CMOS battery or flip the jumper on the motherboard to clear that. That could work, if you can keep people away from your motherboard.
Windows - There are programs that can boot from a disk that will reset your password outside of Windows. If you aren't too terribly worried about it, a strong password should do the trick.