Passport won't mount after power failure

After a power failure duing the night, the Passport WD500MT won’t mount using firewire or USB.  It is seen on Disk Utility using USB but I cannot access the drive.  Disk Repair using USB connection doesn’t correct the problem.  Have rebooted the computer, but no connection made.  Have had power failures in the past without this occuring.  Suggestions? 

were you using tm to back up to the drive?  if so, then you most likely corrupted the file system.  if you can see the drive in disk utility, I’d try to do a partition and format on the drive, and see if it works.  of course you’ll lose the data you had on the drive.  if you need the data you try and find some partition recovery software and see if it works. otherwise just repartition and format the drive.