here are the steps to reformat Windows 7:
1. Backup all your files and settings so that you can restore them later.
2. Find your Windows 7 product key: This should be printed on a sticker on your PC or on the documentation that was included with your PC.
3. Insert the Windows installation CD into your PC, and restart your computer.
4. Press any key when you see the prompt, and follow the instructions to format and reinstall Windows 7.
5. Alternatively, you can use the disk management utility or the recovery partition to format and reset your Windows 7 device.