If you are running a Microsoft Windows operating system on your computer, then you are most likely aware of the fact that your PC will have a Product ID. This Product ID is a system specific alphanumeric code which is derived/calculated based on the Windows product key you use and the hardware configuration of your Computer. In simple words, Product ID is the alphanumeric code that you see when you Right-Click on the My Computer icon and select the Properties option.
1. Goto Start->Run and type the following in the Run dialog box

2. After you open the Registry Editor, navigate to the following key
HKey_Local_Machine\Software\Microsoft\Windows NT\Current Version

3. On the right hand side, you can see an entry by name ProductID listed under the heading Name.

4. Double-Click on ProductID, a dialog box will pop-up showing your Windows PID. Now you can delete the original PID and enter anything of your choice.

5. Once you are done, just click on OK and close the Registry Editor. Now you can see the altered Product ID in the Windows Properties window.
NOTE: This trick works on Win 7, Vista and Win XP

I hope you like this trick.Do Pass your comments