So I take my 'puter to get a new motherboard. The place says okay we fixed it! Got it home, it fired up once. Took it back and four months later they said "we'll find one just like it and sell it to you". I said fine, unwillingly, but told them I wanted the OS from my hard disk on the new one. I expected them to clone my hard disk to the new one. What do they do? Put a pro version of the OS I had on the hard disk with that hacker proggy kmsauto. Piss me completely off. I have zero spare dollars to buy an OS much less a new computer. What would be the best way for me to get my old legal version of the OS onto a new hard disk so I can stop using an illegal copy? I'm okay with cracked software and stuff- just not the OS and not when I didn't ask for it. Know what I'm sayin'?
Let Microsoft know about it. If you have a prebuilt computer from Dell, HP, Lenovo, etc. that is a bit older there is usuaully a sticker somewhere on the case that has your Windows key.
If your able to find it, you could shrink your main partition (if you have room), add a new partition, put all the data you want over there, reinstall Windows with a proper key (making sure not to erase the partition with your documents your saving), transfer the files over to the main partition, delete the temporary partition, expand your new partition, and your good to go.