Best USB locking programs to lock my laptop (FREE)

Hello all,
I am having trouble at work, people stealing infos and docs from my laptop.
Windows security is not enough at all. I am looking for a good free locking (USB key) software for my laptop, that gives me the opportunity to start it as soon as my pc is turned on. Raptor and predator are not good at all cause they do not give you this option.

Please help.
Thank you so much