Iomega Prestige Hard Drive Not Recognized

I've recently noticed my Iomega Prestige 1 TB hard drive has not been showing up on my computer. I have my Time Machine backed up to this hard drive. The last back up shows it was done in April so I'm assuming it's been down since then and I haven't noticed.

I've tried restarting the computer, unplugging the the hard drive but nothing seems to work. I even changed the USB location on the back of the Mac.

The hard drive seems to working just fine. The lights on as normal and I can hear it start up. When I go to Applications I don't see it listed nor do I find anything in Spotlight.

I've been searching for drives but haven't had any luck finding anything for Mac.

Anyone have any recommendation on what the problem can be?