Right now I have a hard drive with windows 7 on it but I'm using a lame OEM motherboard. I would like to move this hard drive over to my new build so I don't have to spend $100 on a windows 7 disk. So if I reformat it can i move it to a new motherboard without any problems?
Windows 7 can only be transferred to a motherboard with the same SOCKET (supports same CPU's). This is considered a "repair" process for when a motherboard repairs and you replace it with the same exact board, or same socket.
If you REFORMAT Windows 7 would install fine, but you would not be able to Activate.
*You can however, at least TRY, because I've heard of it working in some cases even though it goes against Microsoft's official policy.