' XP Cd Key '

I have upgraded from Xp Home to XP Pro. Somewhere along the line the cd key for xp is either lost, invalid or incorrectly typed. Due to myself being the worst procrastinator I have to go christmas shop for the next hour and a half but I'll be back shortly to update my status. I have a old list of a few XP CD keys. Is there a way to check if they're valid or working? Thanks so much.

Hi
The Xp Product Key is usually attached to the documentation that came with your Windows Upgrade installation disc, so it should be pretty easy to find.

To see what product key is currently in your machine, if you follow the link that comes next you will be able to download a programme (free of charge) that will reveal all.

http://www.belarc.com/free_download.html

Regards
paws

I right click properties on the MYCOMPUTER icon and see, Microsoft Windows XP Professional; Version 2002; Service Pack 2. I had installed xp home edition on these two computers. A while back i upgraded to xp pro but the pc now can't validate some certification or authentication. I called microsoft and they talked circles around what i was saying. I got no where. I have the XP Pro CD Key (which isn't valid?.. used it once?) and the Home edition cd and CD Key. Microsoft said i didn't have XP Pro on my computer and i needed to reinstall and use the same cd key????? What is that?? I'm not an idiot I know this pc has xp pro, IT'S DIFFERENT from home edition. The basic reason why i'm trying to do this is to get any more updates for my pc (and because it's fustrating not having the XP PRO SP2 cd when i bought it not so long ago). I used that software website above and it gave me (among many other things) a code microsoft said was to home edition, some long series of numbers. My xp pro and home cd keys do not match. Corporate Greed will not get me.