Computer Virus?

[candlelight]

Hi, I was hoping somebody here might know about this. I'm pretty sure one of my kids downloaded something on my other computer and it's all screwed up now. The only thing you can type on the computer is, "I like it in the ass!!!" I'm totally serious. No matter what key you hit, that phrase just types itself over and over again as long as you're hitting keys. I've run my Norton and can't find anything infected. Checked add/remove programs, can't find anything there. Does anyone have any idea what this is and how to remove it? I'd appreciate any help I can get. I really dread the idea of calling my computer guy and explaining this. Thanks.