You may have a problem on Ebay if you include the OS with the sale. Given Micorsoft's EULA (End User Lisc. Agrrement) you can't resell Windows. I would just reinstall Windows, as outlined above, and then do not activate it. Let the new buyer worry about that!
On second thought, just sell the laptop with no OS installed and guarentee that the laptop is no DOA or your money back. If the new owner was able to use your key and activate...you lsot your Windows key and reactivation on your new puter. If you don't care and have a second copy of Windows then just install and not activate. Is is a Dell? If it is the OS goes with the puter anyway.
Noli Nothis Permittere Te Terere!!
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