Ahh, then the traditional advice applies. Open the case, remove the hard drive, and try attaching it directly to the motherboard ports (if you only have a notebook, borrow someone else's PC). That will distinguish between a failure in the IOMEGA portion of the device and the drive.
If the drive yields its data, copy it quickly in case the drive is on its way out. If it does not, then there are various avenues to recovery, with the direction depending on the first question: is the physical drive seen in the BIOS / in Device Manager?