When your computer (usually involves a Microsoft product) decides to print or display a screen full of unrecognizable jibberish. This often will happen for no apparent reason and at the worst possible times, like when you are trying to save something important or watch porn. This usually leads most people to either destroy said computer in a fit of uncontrollable rage or break down in tears, whichever works better.
I was trying to print out my weekly inventory report and then, BAM, computer vomit. Where's the blowtorch?!