What kind of system? Windows 2000? XP? If it is any one of those, be sure to logoff at night. But if the techno geek is good, you will need to delete the cookies, history, and other things.
But do not think this is a safe answer. If the company has suspicion that you are doing something wrong, they can examine your computer from upstream, and pull your information in real-time and track where you are going. Deleting all the stuff locally will stop the busybody... but will not stop the educated IT Jedi who knows the force.
also alot of companies track your internet usage.
I have seen 10 people fired from a company in my companies office park,
for going to adult sites. your IT dept. doesn't need to see your cookies or history on the pc they can tell where you go from there firewall logs.
To Marsupial moderator: I must meditate on your sage wisdom for answer.
To Junior techie: thank you.
To Super moderator: the force is strong with this one!
To junior techie again: I'm safe in that area.