How do I change the product code on an already activated computer?

http://articles.techrepublic.com.co...

MWCC - thanx for the info. I had used the product key provided to me by this machine's owner, and it turned out to be the wrong key. Now I have to use the correct key. What is curious is that the install, with a bad key, activated with no problems. How is that possible?

As article posted by MWCC, changing the product code will deactivate windows.

How do I change the product code on an already activated computer? Why would you want to. If not broken don't try to fix it. Unless you are going to do a complete reinstall. ----------------------------------------------------------------------------- I had used the product key provided to me by this machine's owner, and it turned out to be the wrong key. Now I have to use the correct key. What is curious is that the install, with a bad key, activated with no problems. How is that possible? The key they used was probably good for the cd (version) they used to install xp. Unless they also gave you the exact cd as well. Each version requires its own set of predefined keys. This is going to be over simplified: If you install blue widgets you need blue keys Yellow widgets need yellow keys. If you install a blue using a blue key but have a yellow COA on the machine, you can go to Microsoft and download their "Key Updater" You then enter the yellow keys. Microsoft takes a close look at the software.....if legal will update the key to match your COA. Updating the key to match the COA is legal using MS updater. Changing the key is illegal. Changing and updating are two different animals. You should retain your activation updating the key. The updater is used by people who install xp using the same key on numerous machines using an image. Once installed the keys are updated. I have a feeling the key you were given was for their own cd and not yours. -------------------------------------------------------------------------