If you are concerned. The odds are that it will be a software keylogger. As previously mentioned hardware are more costly, and sometimes harder to install. Take a few minutes when you first get on the computer and download and run SpyBot S&D. While I've never had a keylogger on my system and cannot test it's claims, it does claim to remove keyloggers.

I don't know how your lab is set-up. I have access to 4 labs, 3 of them until 10 and the last is 24 hours.. two of the labs open until 10 are ghost labs. I can go in and ghost them with whichever OS I want and use a fresh install..... Maybe yer school has something like that. it'd be worth looking into.