Unexpectedly lost graphics, but theres a story to the issue.

So this gateway that i picked up had onboard graphics. Its running xp home with an amd cpu. I had a nice geforce graphics card that was pci express, and i decided to put it in. I loaded the card, and booted the system. Things went good until the first restart, at which point the monitor didnt come on. I switced the vga cable back and on it came. so after booting into windows, i restarted, and the monitor did it again, this time wanting the new pci express card. So I switched it back, and booted into windows. Now, to try to prevent this on each restard, I went into device manager and disabled the onboard graphics from the windows side. After restarting, it now favored the pci express card.

2 weeks goes by, and all is well until 2 nights ago. I shut down the pc, and when I wake up and go to turn it on, i get no display from the monitor. So, I climb underneith the desk and switch the vga cable back to the onboard graphics, and the monitor comes on. Only this time, after the windows loading screen, it just goes black (im assuming because i disabled the onboard vga in windows). No matter what I do, it wont boot to the pci express card, and everytime i boot to the onboard, they work until windows starts, then the screen goes black. I tryed to boot into safe mode a few times, and when loading the safe mode files, the pc freezes on mup.sys EVERYTIME.

Any suggestions?