Deleted Windows

The Windows directory (Win98SE) has been deleted by a customer in error! Normally I would simply reformat and reinstall but this customer paid a large sum of money(?586)only 6 months ago to recover data via a data recovery clinic and still has not understood the importance of backups.
Is it possible to restore from the recycle bin in Dos and if so what is the best way of doing this bearing in mind that the recycle bin is normally hidden? I have not actually had chance to visit this system (appt for Wednesday).
Look forward to best help.