Possibly. I've done many a motherboard swap and had no issues, but I've also had as many if not more that did have issues. What it boils down to is you own a 3rd party OEM. Dell. And in Dell versions of Windows, the key is tied to the motherboard itself, not to Windows. The original board will include a bios chip specifically for Dell, so using a vendor board, with a vendor bios might raise some flags. If you do have problems, contact Microsoft, explain it's a motherboard replacement, not a secondary new build, and they may issue you a new key. At worst, you'll need to purchase a new copy of Windows. By replacing the motherboard yourself, with a non Dell certified and installed by certified Dell repair, you will now own your pc outright, technically it will be a aftermarket pc, in a Dell branded case, not a Dell XPS, so it's doubtful if contacting Dell directly will be of any use.