Is Overwritten File Recovery Possible?

If a file has been accidentally overwritten with one that has the exact name, is there any utility or other means to recover the over written file? Is there any way w/ windows 98 to restore the system or registry (eg. sysreg /restore?) to a previous date? Does anyone have experience w/ this? FYI, there has been no disaster recovery effort made, so there are no backups available to restore from.