My data has disappeared from my external hard drive!

I couldn't find anything in the threads to this exact problem. Recently all my data disappeared from my Iomega external hard drive. I only see one picture left! I had pictures, videos, and applications on there, like my copies of virus apps, games, ect. I recently added more to it because I wanted to put Windows 7 on my pc. I ran Superanti-spy and it found some adware/spyware stuff, but nothing major. Is there a application to help me get my data back? The computer sees my Iomega on E drive. This is normal. The weird thing is, I clicked on it thinking it was on, and found only one picture. Then I noticed that the external hard drive was not turned on! Somehow it opens when it is not turned on! I hope somebody can help.

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 12:18:18 PM, on 4/21/2010
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v8.00 (8.00.6001.18702)
Boot mode: Normal


Edit by chaslang: Inline HJT log removed. READ & RUN ME FIRST. Malware Removal Guide sticky not followed.