WD external hard drive saying "this folder is empty"

Greetings!

Since this afternoon I've been having trouble with my external hard drive. It first started when I clicked on one of the folders in it and was told the folder was empty. It's the main folder on the drive so it should have had quite a bit of stuff in there.

I restarted my computer to see if that would fix the problem but it made it worse. Now the drive takes several minutes to load and when I try to open it it says "this folder is empty". Not only is the original problem folder not visible, all folders are now gone. It's as though the whole drive is empty.

One time when the folder loaded I could see that there was only 3GB free out of 2.7TB so I know the files are still on there. Unfortunately it won't even display this anymore. It just says "Local Disk (F:)" but doesn't display the status bar showing how much of the drive is used.

I tried running a disk check but it said "The disk check could not performed because windows cannot access the disk".

I also tried to open a previously opened file from the drive but was met with this:
"The drive or network connection that the shortcut '' refers to is unavailable. Make sure that the disk is properly inserted or the network resource is available, then try again."

I checked that the cords were plugged in and tried plugging it into different USB ports which both failed. My other external USB works fine when plugged into the same spots.

My specs are:

Toshiba Notebook
Intel(R) Core(TM) i5-2410M CPU @2.30 GHz 2.30 GHz
4.00 GB RAM
64 Bit Operating System
Windows 7 Professional, service pack 1

I'm completely lost so any help you could give would be greatly appreciated!

Many Thanks!