Like the old one was prebuilt, and it's only three months old, and you want to use it's copy of Win 7 on your new one? Just to clarify, if that's it, then technically, no, unless you built the last computer and it's a retail version of Win 7, not an OEM version. OEM version is tied to the motherboard, Retail is supposed to be on only one computer at a time, because of how new it is, you might be able to call M$ and they might transfer the Win 7 to the new computer. Worth a shot.