Is this a pre-built system or something you put together? If you put it together remove EVERYTHING non-essential to the system and then install. If that works then add everything back in ONE at a time please with boots and drivers between each device. Also you really need to get to know a Virtualizatiohn software such as VMWare, VirtualPC or Parallels any of them out there. They allow for testing your disks and installation without the harm or fear of loosing your system\data. As for the Vid card> That thing is HUGE please measure your box before you buy one or two of them.