I recently replaced my broken motherboard along with the processor and video card. When I try to start up, it gets to the start up windows part, and reverts to the error screen where it says "you may have installed new hardware or windows was shut down incorrectly." When I try to run auto-repair, it says it cannot fix the problem automatically.

Is there any solution to this problem other than reinstalling windows? I don't have a windows 7 installation cd, it just came with my computer. Is there anyway to use that code more than once?

Thanks in advance.