your new video card is an AGP card correct? if it is its an AGP 8X card.
does your motherboard support AGP 8X?
run everest and it will tell you everything you need to know about your PC.
Also pop the side of the case off and look at your powersupply, on the side it should have some indication of the Wattage.
get back to us with that info.
the X1300 Series requires a 300 Watt PSU or higher.