its tech. about gaming..

I have a dell xps m1210 laptop. 4 gigz ram (i heard vista doesnt see all 4 gigz, oh well..) 2.0 ghz core 2 duo processor, geforcego 7400 series video 256mb. not exactly a gaming machine.. but here is my thing. I actually bought this computer for a friend of mine. Than i bought it back. and wonderful people down @ dell decided that a built in harddrive recovery iSO image was useful. So i ghosted the harddrive, figured it get rid of any crappy programs and/or viruses and porn he dl. well.. all was fine, runs great, still has a dvd codex- awsome. well. it lags. it runs a lil slower than i remember and i play world of warcraft. and i used 2 b able to play at mid range specs at widescreen 1200x800 24x24x2 multisample at an average of 50 fps. with minimal interface lag, if any. after the ghost, and reinstalling new drivers and the minimal windwos updates.... im lucky if i get 5fps at those same specs. now everything is turned down, at 1200x800 24x24x1 multisample.. at an average of 20 fps.. idk why this is happening, i removed norton bc i hate it, and my free yr exprired anyway... i was considering overlocking.. but idk how well that works on a laptop. i DL a program called Rivatuner http://www.majorgeeks.com/download737.html and i detected my default settings. ::: on performance 3D im @ 900mhz for memory, and 450 mhz for core clock. no idea... should i play with the settings?!? maybe theres something else i can go to reduce lag plz, any suggestions/tips would be amazing thanx in advance!