ASUS P8H77-V LE is the motherboard model I have. When I built my computer I hadn't realized that the mother board supports crossfire but not SLI and I put a GTX 560Ti in it. I didn't learn that I cannot SLI the cards together until 4 months later when I started looking into adding a second GTX 560Ti to my build. I want to change the motherboard to a better one that supports SLI and higher quality graphics cards then get the other GTX 560Ti and SLI them together. Would I need to get another Win 7 OEM or would the existing install work because I'm only changing the motherboard and not the CPU etc.?
It should, however, you may need to reactivate it with Microsoft. The system fingerprint that is used to activate Windows relies on several pieces of hardware and the MB is one of them. While I haven't had any issues, I have heard that it is a simple process, but may be time consuming.