Hi
If you have a genuine Toshiba Windows 7 recovery DVD or used the Recovery DVD builder and use this on the correct Toshiba laptop you do not need to know the Windows 7 key which is not the same one printed on the Windows 7 label.
If the PC is still working there are several programs which will tell you what the Windows product key is
(but many AV programs will consider these utilities mallware)
examples:- magical jellybean, Produkey etc
regards
Mike Barnes