Help! Can't change Sims 2 screen size + GraphicRules.sgr to edit

Hiya! No you are not doing anything wrong. The files need to be altered to work on newer hardware. You can check out my post here http://forums.thesims.com/en_US/discussion/944100/the-sims-2-lags-too-much#latest to get the file path you need, along with a site linked to help you know which things to edit. You will also need to edit the video card files, instructions for that are also there. :)