I had a problem to change the product key of Ms Server 2003 and it's done perfectly, with following method and you dont need to reinstall the servers. 1. Click Start , click Run , type regedit , and then click OK . 2. In the left pane, locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\Current Version\WPAEvents 3. In the right pane, right-click OOBETimer , and then click Modify . 4. Change at least one digit of the OOBETimer value to deactivate Windows. 5. Click Start , click Run , type the following command, and then click OK : %systemroot%\system32\oobe\msoobe.exe /a 6. Click Yes, I want to telephone a customer service representative to activate Windows , and then click Next . 7. Click Change Product key , type the new product key in the New key boxes, and then click Update . Note If the previous Activation Wizard screen appears again, click Remind me later , and then restart the computer. 8. Repeat steps 6 and 7 to v...