There is no need for the product-key at all to restore the Windows bootloader. Borrow a Vista/7 disk from one of your friends, boot from it and start the recovery console, then launch the command
Alternatively you can download an evaluation version of Windows from the Microsoft website and use that to restore the MBR.
I have a few questions:
- Why are you using Lilo instead of the standard Grub2?
- If you want to use Lilo, why did you uninstall it?
- If you want to use Grub, have you installed it to the MBR using