Possible Beagle or Rootkit - desperate for help

Can't open NOD32, Windows Defender, Comodo Firewall, not even AVG Anti-Rootkit and beagleremover. NOTHING. "Not a valid Win32 application". My browser's homepage got hijacked, and my USB pen drive has been infected by a .com virus I don't remember (I'll look at it later).

Rootkit Revealer found srosa or something along those lines, but I couldn't get to the registry keys.

Nor can I find wintems in my system32 folder nor hldrr in my drivers folder. How could it be? Those are the symptoms.

Enough vague information though, I've ran MGTools, I have the log.

My computer is so slow I could barely get to type this. HijackThis has mysteriously vanished.

And no, Avenger doesn't work. Tried it from the other similar topic, it was no good.

I also ran Symantec's Beagle removal tool, nothing detected after hours of scanning.

I got infected by opening a fake setup program.

I am desperate for help, nothing seems to work, and I really want to avoid formatting my HD. I would be so grateful if someone can get me out of this.

EDIT: There is not even sound on my system anymore! I can't hear anything nor can I bring up the audio control panel, I get an error message. I have never seen something like this before, it's driving me insane.