Cool idea Huntondoom
This game could have viruses for opponent players. You choose with who you want to play (let's say a worm) and play "against" it in a card game. If you loose that session, the worm gets released - of course you will have to pick simple yet destructive worms that could revert the damage after winning a rematch with that worm.
Or, you could have a difficulty level - Lame/Easy/Medium/Hard/Unrepairable, where in each category you would have an array of stuff to do with the computer depending on the difficulty to fix that problem. Let's say for Easy you could move all the icons from the desktop to a folder on the desktop - very annoying for those who have icons set up in some way
or create shitloads of folders somewhere...
Medium could be disabling of the task manager...
Hard could be swapping the mouse buttons...
Unrepairable could be destruction of the partition table
Lame where you don't loose and computer stays unchanged...
This could be not only very annoying, but eye opening making you learn to fix the system, the hard way
Like Huntondoom said, if you need help with writing such tasks I'd gladly help when I have time