|Why would you install both Win7 & Vista? Win7 is an improved version of Vista....it's basically what Vista should have been. Anything you can do in Vista, you can do in Win7. Vista is just a waste of space on your hard drive.|
Other than that, it sounds like your system is overheating & throttling. Since you said you replaced the baord, my guess is you didn't properly attach the heatsink to the CPU.