Downgrade Windows Vista Business to Windows XP Pro

Prepare;

1. Genuine Windows XP Pro Product Key
2. Windows Vista Business Product Key
3. Microsoft Hotline No. 1-800-88-6295

Step;

1. Call Microsoft and talk to customer support
2. Tell them you would like to downgrade from Windows Vista Business to Windows XP Pro
3. Provide them the Windows XP Pro Product Key and Installation ID from the Telephony Activation Screen
4. Provide them the Windows Vista Business Product Key
5. Here you go, they will provide you the Windows XP Pro Confirmation ID and key in into respective box
   
6. Click Next and your windows is now activated