athabasca :
i want to reformat my laptop, i have a good windows 7 number but no cd, how do i do this
Get the Windows 7 ISO here:
http://www.w7forums.com/threads/official-windows-7-sp1-iso-image-downloads.12325/
Burn to DVD and go for it. Activate with your existing key.
Be sure you download the same version that is currently installed.