Explorer.exe won't run on startup

So, when I turn on my computer, everything is fine, until I log into one of the user accounts. The screen is black except my documents folder is open. This, of course, means Windows Explorer isn't on. So I ctrl-alt-delete, choose Task Manager, applications, new task, explorer. This is a bit bothersome, since some of my other housemates pull me away from my business to help them out. I don't think it's any kind of malware. I did full scans with Ad-Aware (and Ad-Watch), Avast!, Avira, and Spybot: S&D. I clear all my cookies and anything else that comes up. I did get Zlob out about a week ago, however. In a last attempt, I put a copy of explorer.exe in my startup folder, but still, no luck.
I am running the following:
Microsoft® Windows Vista™ Home Premium
Version 6.0.6000, Build 6000
HP-Pavilion
System Model: GG781AA-ABA a6110n
System Type: X86-based PC
Processor: AMD Athlon(tm) 64 X2 Dual Core Processor 4400+, 2300 Mhz, 2 Core(s), 2 Logical Processor(s)


If you need any more information, please feel free to ask.

I also uploaded a .log file of my HijackThis using Trend Micro HijackThis v2.0.2

Thanks in advanced

 

A malware check is probably a good idea. :cool However the malware experts here on Majorgeeks will never find your log in here because they rarely check outside their forum. :-D They have their own section on Majorgeeks, you see. So the thing to do is to start a thread again but this time in that other sub-forum. These guidelines will tell you all about how to do it. Good luck.