FIRST TAKE CARE WHEN CHANGING THE WINDOWS REGISTRY. YOU CAN MAKE YOUR INSTALLATION OF WINDOWS UNUSABLE.
For whatever reason you may have, you might want to change the Registered to: name or the organization that appears under System Properties in Windows XP. It is very simple, just follow these steps.
1. Click Start, Run, and type regedit in the open box.
2. In the left pane of regedit navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion.
3. Look in the right pane for RegisteredOwner to change the “Registered to: name” or RegisteredOrganization to change the Organization name under the registered owner.
4. Highlight the one you want to change by left clicking on it. Then right click modify and in the Value Set box simply type in what you want to appear in System Properties.
5. Open System Properties and your new settings will appear.