Moctezumabear

I am i desperate need of some assistance, I have tryed tierdly to make the ATI Radeon Mobility X1400 work with my DELL E1505. My ATI Radeon Mobility X1300 and the nVidia GeForce Go 7300 both work fine on the system (with their respective drivers), but for some reason when I install the ATI Radeon Mobility X1400, my notebook doesn't even turn on... the power led turns on for 3 sec then it just turns off on its own. I updated my laptop with the latest BIOS and ATI Video Drivers from DELL. Made sure nothing is left when installing ati driver. I tryed changing the video card 3 times from x1300 and x1400and back to x1300; yet, the x1300 always turns on.... Please help.

P.S. When I turn on the Laptop with no ATI drivers... the BIOS still sees an ATI Radeon X1300 is this ok...