I replaced the motherboard on my Dell Dimension 5100 computer. I am running Win 7. A pop up window keeps asking for a new product key. The computer still works fine otherwise, it's just annoying. I have heard that if I had the original OS, that the computer came with, I would need a new license key. The computer originally came with Win XP, and I purchased a licensed Win 7 for an upgrade, before the motherboard died. Do I still need to purchase a new Win 7 license, or is there a workaround for this? This stinks if I have to. Being Win 7 is out within a year, probably Win 10 would be the way to go if I have to change now.