It was just a simple QBASIC program (that's all that was available on the Computer Room machines) running under my own login, which would write usernames and passwords to a text file in my user directory. I figured that I'd harvest a few passwords until someone got frustrated enough to call for the IT admin, at which point he would try to log in and reboot the PC when it failed, apparently "fixing" the problem and erasing any evidence of my dastardly crime.

I was right, and for a few glorious days I got away with it... until one particular arsehole picked on my best friend during recess, and I used his stolen credentials to log into his account and trash his files.

Long story short, I ended up getting expelled, which by a curious confluence of events put me on an unorthodox path that completely changed my life. Funny how things turn out.