uninstalling windows 7, not reverting or installing anything else

Question

I am borrowing a friends laptop and have my own version of windows 7 installed. Now I am returning it and want to uninstall the os. My friend will install his own operating system at some point. I want to return basically an empty computer. How do I uninstall windows 7 and completely empty the computer without replacing the os or reverting to a previous os or something?

As a follow up question: Don't you only have a few installs of windows 7 using one key? Is it possible to do something like deactivate the product key on that laptop or something? I'm not really sure how this system works. Thanks for all your answers to the previous question

Answer 1

Download Darik's "boot and nuke" live CD at http://www.dban.org/ Boot to disk and follow prompts. You will have a computer that has nothing on it.

Answer 2

This is based on Windows XP clean installation process:

During the install process you are able to format your hard drive and create the partitions to install on. If you perform this step and then stop, then you will have given back to your friend a "clean" computer.

An alternative approach is to create a boot disk, boot up, and perform a format. This is simple (there are also boot CDs and flash drive) and much quicker. You can look online for various sources of boot disks.

Answer 3

start a new setup of a new windows with cd booting ... then format hdd create a new partition with same size then exit formatting process (cancel new formating process) ... your windows will be deleted and so computer have not a OS installed ;)