lol who sold you/parent that pc? another compaq? PCI cards are generally slow , the fastest you would find would be a voodo 5 PCI , just slightly faster than a geforce 2 . you should trade in the mobo for a new AGP slot mobo . If the geforce is an MX 420 return it for a geforce 2 ultra [ which is the same thing ] it would be cheaper . Geforce 4s are still lot better than FXs tho . stick to the non fx cards and you will be a happy gamer .
Make sure you get the RIGHT agp slot , there are 1x 2x 4x and 8x .