Alright, here goes.... I once had a older PC which I upgraded from Home to Pro. The old computer has surcomb to gravity, and now I got this new PC. I found the XP Pro Upgrade CD, I want to install that on my new PCs XP Home OEM. My concern: Since my old PCs CD KEY has been registred to Msoft. I am worried of upgrading the new PC, and finding I am not qualifed for future updates. As the XP Pro CD is registered to my old PC. Is it still possible to update? Or do I have to re-register with Msoft via tech support?

You probably will need to re-register with M$. Just explain that the original PC is no longer used. i_XpUser

You must understand that REGISTERING is different than ACTIVATING. XP is the first version of Whendoz that requires "activation" for use. A drastic change in hardware will trigger the need for reactivation. Since it has been such a long time, you probably can simply get on line and reactivate it. I'm assuming, of course that you actually have a legal copy in the first place.

Yes, I do have a legit copy, "name". That's my whole gripe, I've paid $199 for the upgrade CD. I don't think there is a on-line registration option. XpUser seems to have confirmed what I thought. Dang, I REALLY don't like going to tech support for something like that. Anyone know what they charge a minute?

Do you really need XP PRO?? It doesn't add many advantages to the normal home user. Is it worth the risk? Sorry, I do not check for private messages

You can look around here to get more info about what you need to do: http://www.microsoft.com/resources/howtotell/en/default.mspx "Since my old PCs CD KEY has been registred to Msoft......" I don't think Microsoft has any idea of what your specific Product Key is - all that concerns them is whether it is valid or not - I don't think they keep any record of it if it is valid, but they do have lists of XP Product Keys found to have been used fraudulantly, and if you use such a Product Key, your validation will fail, and you cannot Activate Windows, or use Windows Update. If your validation fails, and you have a legitimate CD, Microsoft can assign you a new Product Key if you meet the requirements. You don't have to Register, but you do have to Activate. I have never bothered to Register - maybe you have to supply a Product Key if you do that, but I doubt it. It's the Activation that has specific relevance to your computer mboard and whatever is connected to it. If you change your hardware drastically, you have to re-Activate, but smaller changes can be tolerated without having to do that. e.g. If you changed to a mboard with the same chipset, used your old cpu, ram, and cards, especially the network card, you would probably not have to re-Activate. Info about that can be found at the above site.

I've done that for a friend ,installed xp on a new pc. after the old one went south. and it activated first try. there are some oem versions that you'll have to call the free 1-800-microsoft and tell them that your reinstalling and it wouldn't let you activate online. and they most often will give you whatever number it is you need, for no charge. since you are just "reinstalling".