HELP! bootcamp and installing Winows on replacement Mac

I betting someone on these forums has run into this before. Please tell me what you did and how you resolved this.

Here is the situation. I previously had a Macbook Pro and sold that and got a 24 inch iMac. (I no longer needed portable Mac and wanted a bigger screen). So i went to install bootcamp and Windows XP like i did on my MBP, using the same copy of windows. I thought no harm no foul there.

Well apparently it spit an error at me when i tried to activate Windows. I guess i can't use that product key on my new iMac. Anyone else run into this? There is no way in HELL i'm buying another license to use this copy of Windows on my new iMac. I could see if I still had my MBP as i would have 2 machines running it.

Have others had to buy a new product key (license) when doing this?

I use Windows for gaming only by the way. And so i can use my VectorVest also.

 

Thank you all for your suggestions. I have gotten my resolution form another poster in the iMac section of the forums.

There was a part in the activation screen where you had to click "telephone". Then it gave you a code. you enter that code to the automated telephone system, it asks you how many PC's you are running that particular windows on.....you of course say 1. It then spits out another code you enter into the activation window (it sits there and waits for you to enter the code). And prestooooo... my windows is now activated free and clear.

Problem resolved. Again, thank you all for your responses!

(a side note: this was a retail version i bought on its own when i first got my MBP)