video card problem g4

hi well to it…

p3 750 512ram
tyan trinity 400 1.07 s1854
generic lan/sound cards pci
350wat power supply

any way im useing a voodoo5 5500 and i bought a Xtasy geforce4 mx 420 64mb and i followed instruction in box and when new card is in the monitor gets the grid like its getting no signal(white squares) but the squares are purple?? and motherboard beeps funny, went to website under beep coedes its the code for video problem,but didnt say how to fix.i put voodoo back in and works fine?
i read some forums and deleted everthing in reg under voodoo and 3df still new card wont work? should i install the g4 drivers before installing card?? am i missing something please help!!!

dude bad gf card return it