xp microsoft key number?

If you reformat then you will require an xp disk.
If the operating system was preloaded then you should have obtained a "reload disk" and would use this instead of a reformat. Alternatively you could contact the helpful people at Microsoft and they may send you a disk if the code is genuine. The only alterative left would be to purchase a genuine copy of xp and install. Personally I would avoid ebay as too many pirate copies that will not allow updates due to Microsoft authentication software adding to your problems and the same would be for xp key generation software.

Tom
June 2006

ebay

Kirstein
June 2006