I just changed a hard drive and power source out of one tower to another and the tower i put them in had vista the new drive has Windows 7 windows will not boot and i can't get it to boot from the hard drive :gun:
You can't put a hard drive into a new system that already has an operating system installed from a different system as the hardware is all different. It will either blue screen or boot loop on you. You will need to do a fresh install of windows.
