Installed pci video card and I get BSOD with 0x0000007e,

I picked up this used computer off the internet that was suppose to be running right out the box. That was before he shipped it using a handful of peanuts and 2 sheets of plastic for padding. Anyways I get the PC in and It powers on but nothing but black screen. I installed a pci vga video card and the monitor came on. I saw the XP logo and then, BAM! BSOD, with the same old saying sbout "Sorry for the inconvience, if you installed new hardware please check the that the drivers where installed or press "f8" to boot in safe mode etc. then the technical error message. .......0x0000007E. I rebooted and got the same thing with the BSOD. Then I stopped working on it and the next day after emailing with the person I bought it from and he said everything worked fine when he put it in the box to be be shipped. So, I took the video card out and put everything back to the way it was when I received it. I plugged it in and it booted up and the monitor powered up. I was shocked and thought it fixed itself overnight and cooled off, reset of whatever. Everything was working fine, so I started downloading Windows Updates and all of a sudden the PC shutdown and restarted. The monitor powered up again as well. Two minutes later it shut off and restarted but this time the monitor went into sleep mode. I am thinking it has to be that the motherboard was damaged during shipping.