Microsoft Windows XP?

Microsoft founbd out that my version of Windows is fake, what will they do?

What can they do?

Microsoft Windows XP?computer

The only problem you are going to have with that is, they are limiting some of the updates to 'Genuine Advantage' users only. Otherwise you will still be able to get critical updates and security updates. They aren't going to do anything unless you are running a corporation from pirated software, home users pffft, not concerned. Apparently you have no idea that China is run on pirated software, can you imagine how much money they lost on that one?

Microsoft Windows XP?free spyware

Well it means you are using a fake OS and you are not legal. They could take legal action against you. I would tell them how you got it and it it as all above board and you are the dupe then they may give you a proper one in its place.

Good luck.
In short...NOTHING!! They might ask you to purchase a copy, but thats about all.
They won't do anything, you just won't be able to download any updates.
They can't do nothing but bother you with a lot of pop ups asking you to purchase a legal copy. And you won't be able to download any updates or installing new releases like Internet Explorer 7. There is a program that allows you to validate your version (i think this is not legal) but it works. I have to confess i had the same problem, but i didn't buy a legal copy. I borrowed one from a friend.