Repairing a recovered XLS file

Hello guys, here's the deal: We had a major HDD fault in a laptop the other day... Pretty messy, (the laptop was our chief accountant's, and she's a paranoid x) ) as most of the data on the harddrive was invaluable. Using a recovery software, however, we've managed to get out about 80% of the info and transfered it to a mobile HDD. Almost everything is allright, except for a few xls/doc...