If you're at your girlfriends house you shouldn't be downloading shit onto her computer.
OT: If you do, then the parents will obviously find out, if it's a good parental control system.
My girlfriend is trying to update Java and a few things on her computer account, and her mom won't let her because she thinks everything gives viruses.
If you can afford, buy a vps/dedi and access it through the internet browser? If you can access your dedi, you won't have parental controls on your dedi and you can play/surf from your dedi on her computer.

