GTX 460 - Windows Won't Start

Hey, new to computers. Finally bought a GTX 460 and a new power supply so I can play Borderlands 2 and Guild Wars 2. Anyway, whenever I install the card and upgrade the drivers Windows won't load anymore. It gets to the Windows screen, freezes at welcome and crashes or just crashes after the Windows load screen. Most of the time Windows just tells me that it can't start up and requests a system restore, which doesn't help. Occasionally I was able to get to the desktop and through the Device Manager it just lists the card as my standard VGA display adapter, whatever that means. I have an integrated AMD HD 4200 or something and I've disabled time and time again. When I was able to go to the desktop and run "Can You Run It" program it says I don't have any dedicated video RAM and lists it at 0.0MB while it lists the other features of my video card. So I disable, shut down, insert video card, update drivers, restart, windows says it can't find the start up and requests system restore. Anyone know what's going on? I was reluctant to start investing in my PC for reasons like this, but if I can figure out the hard stuff first I'm sure things will get easier.