A way to recover an OS after a quick format?

Ive managed to get myself in a dumb situation and im hoping someone here can help. Ive formatted and half installed XP onto a laptop, and realised that the XP product key isnt stuck on the bottom where it should be. Now I have a PC with half a windows install and no CD Key to finish the job. Does anyone know of a way to either recover whatever file holds the key info, or get the origional install back running so I can find the key using some software or something?

Any help on this is much appreciated, Im pretty stuck myself.

If you have formatted, and are currently at the point during the install where it is asking for a product key, you can't go back to the previous install. At this point the install is almost complete, and the previous install is already gone. Can you contact the laptop manufacturer and see if they can give you the key? I assume you don't have the certificate of authenticity documentation that usually comes with the system?

Your going to have to get a copy of getdataback or r-studio and then just get your data back you should be pretty successful, you should get about 99% of your data.