Help a newb plz. Videocard / driver related

Recently i have bought a Geforce 4mx 440.Unfortunately it couldnt fit on the agp slot of my motherboard.So i bought a new motherboard of elite group.the computer regognizes the card and its working properly.But the games still dont run system is not so good(733mhz. 128 mb ram,20gb hard drive, and geforce4 mx 440).But some old games arent running smoouthly.virtua tennis, nfs hot pursuit 2 …graphics options are all set to low.these old games dont need a better system than mine.what should i do?Should i buy a new motherboard?i dont think ram or cpu is the problem.pls help me.:frowning: