Sims 2 screen resolution problem

I play sims 2 on a windows 7 laptop and when trying to play the game, it is stuck on a screen resolution of 800 x 600 so i cannot play it anymore. I need to sort it out as I just bought a new expansion pack so it will be a waste of money if I don't get it working. I've heard it's to do with a windows update and I've been reading that to sort it out you have to remove an update, however I don't want to do that as it's a family laptop and I haven't got administrative capabilities on my laptop Is there anyway to sort this out without removing updates? I've tried changing the graphics rules but that doesn't work. Also, I have no problem like this on my other computer but that computers for work, not for playing games. Please help!