Some liscenses are for 1-2 CPUs, meaning you can have the OS installed on only that many computers at the same time. If you've got one that's only good for 1 computer, then you'll have to put a different OS (which I believe you said you're doing) on your current one, and install XP on your new one. When you try to activate it, it might just let you...I reinstalled XP Home on my last computer at least 3 times, and it activated without problem every time.
When I reinstalled XP Pro on this comp once (changed my motherboard), it gave me a message that I had to call in get a key to activate it, because it had been activated too many times. All you have to tell the guy is that the copy you're using is only going to be on one computer...tell him you had to reinstall 'cause you made a lot of hardware changes...he'll give you a key that you type in and it activates XP for you legally. While you're at it, you can ask him/her how many computers you can use this same copy of Windows on, you might be able to avoid putting shitty ass ME on your old comp...or you can pay to get a liscense to use it on the old comp.

 

Blah ....license this!

I think eery OS I have ever owned has been installed on no less than 15 machines at a time.

I still run update once in a while with no problems.

The main thing is to not register it, do not send error reports, and don't ask MS for any help with it.

Never had a problem yet....I have done this with 98, 98se, ME, XP, and XP Pro.

 

Some CD keys for XP allow you to install and activate it numerous times (Like my old retail copy of XP home)...but some only let you activate once or twice....like my current OEM copy of XP Pro. After that, you have to call to activate it.

 

Try installing the hardcopy onto your new computer. If it doesn't allow you to reregister it via the internet, just call up Microsoft and say that your transfering XP overto a new computer because your old computer is trashed and you threw it away. Like John said, just be sure not to get any help from microsoft on any software related issue and you should be fine.

 

Grrr.. I have XP on the computer i'm on now. I am going to format and go back to ME on this computer. I want to use the same CD key (license) on a new computer i'm building. I just wanted to know if it is possible to move teh license to the new homebuilt one without having to buy a new license. I'll just try and install it when the time comes and see what happens.