1. Restart your computer, and then start pressing the F8 key on your keyboard.
On a computer that is configured for starting to multiple operating systems, you can press the F8 key when you see the Operating System Choices menu.
2. When the Windows Advanced Options menu appears, select the Return to OS Choices Menu option, and then press ENTER.
3. Select the Cancel Windows XP Setup option.
4. Use the Add/Remove Programs tool in Control Panel to remove the third-party software from your computer.
5. After you have removed the third-party software, restart your computer.
6. Upgrade your computer to Windows XP.
7. Reinstall the third-party software after the upgrade process is complete.