Terabyte suddenly blank?

I have a terabyte full of stuff, and I recently went to open a directory via a shortcut and was informed that the drive path did not exist. I opened Computer and saw the drive wasn't listed there. Assuming it had somehow lost connectivity, I switched the drive off, waited for a few seconds and turned it back on again. This has solved this problem when I've discovered 'missing' drives in the past.

However, when I switched the drive back on I discovered that it was completely 'erased'. Nothing is on the drive, and that is confirmed by Computer's space analysis. This is mildly disturbing. What happened to all my stuff?


Operating System
Windows 7 Ultimate (x64) Service Pack 1 (build 7601)

Processor
3.20 gigahertz Intel Core i5-3470
128 kilobyte primary memory cache
1024 kilobyte secondary memory cache
6144 kilobyte tertiary memory cache
64-bit ready
Multi-core (4 total)
Not hyper-threaded

Board:
Gigabyte Technology Co., Ltd. H77M-D3H
Bus Clock: 100 megahertz
BIOS: American Megatrends Inc. F5 03/29/2012

RAM:
Slot 'ChannelB-DIMM0' has 8192 MB

Display:
NVIDIA GeForce GTX 660 [Display adapter]
Samsung SyncMaster [Monitor] (24.0"vis, s/n YCUYHVDZ702086, July 2010)

Audio:
NVIDIA High Definition Audio
VIA High Definition Audio



Edit: I did a scan and found these (picture attached)

Does anyone recognize these or if they may contribute to the problem?

Did you try plugging it into another computer to see what it does? Also, I would get rid of those trojans. You might have a worm of some sort. Figure out what the trojan is, and get a removal tool for it.

Another question: Was it dropped at any time?