I usually handle viruses, rootkits, anything I can happen to catch (or my friends catch on theirs), but this one has me stumped. I could just be not trying hard enough, but anyway:
Started with slowdowns, and me noticing that SVCHOST, one of the many in the Task Manager, would frequently, VERY frequently, be taking up exactly 25% of my CPU usage. I'd end it, and the related service (Almost always NLA), and I'd usually be fine for quite some time, having it pop up again maybe in a few hours, sometimes not at all. This however made me suspicious, so scanning I went. Avast boot scan found a few things that it could not handle, eventually leading to me having to skip them to continue (sadly at the time I did not record what those were, but I believe they were in System Restore). Upon reboot, I ended the svchost process, ran Rkill to make sure (didn't find any if I remember), then ran a full scan in Avast, and again in Mbam. Mbam found a few things, asking to restart to remove. I did, and it never seemed to get to remove them. Always showed up again on the next scan. Avast found a few things, but I knew them to be false positives as I'd created those few programs myself, just messing around. Deleted anyway, as they didn't have any real use. Avast then found nothing.
A few days passed, with little work done in the way of removing whatever it was (Busy, lazy, take your pick), then, after one Windows Update restart, things seemed a bit different. SVChost seemed to be a bit more docile about it running at 25% usage (although still did/does), and now, upon opening Task Manager, RIGHT after opening, my CPU usage is almost always above 30%, then immediately hops down to normal idle speed (0%-1%). I'd simply been refusing it network access at all past this point (actually, pretty much after I suspected it). I had just been playing games, and running scans while I slept, as scanning 2 TB for viruses and having it unpack every zip with Heuristics on HIGH takes quite some time. Every night this week and last, I've ran a slightly different scan than last nights, with no luck. Yesterday, I used TDSS Killer, and it consistently finds an infection in SPTD.SYS, which I obviously can't seriously quarantine or delete.
Truthfully, I'm a bit ashamed, as the real "kick in the butt" that made me post and actually try a bit harder was the fact that now, it seems to be affecting my gaming. It refuses to do almost anything smoothly now, and I have PLENTY of power to do what I'm asking -
CPU: Q9650 775 Cpu, Quad
Video Card: GTS 250-60, can't remember at the moment specifically
and a TON of Hard drives and partitions (4 or 5, each averages 2-3 partitions)
6.0 gb RAM
So please, if anyone has any insight, let me know. I'm completely under the control of this thing, and I can't get out from under it.
OH, also, I ran combofix (changing it's name to make sure nothing happens), but I wasn't watching it intently, so I have only a log I'd be happy to attach, and will try after I'm done typing this. Also keep in mind that I have updated everything before every scan (Mbam, Avast!), and only performed full scans with each.
EDIT: Oh sorry, forgot to mention WIndows 7, x64
EDIT EDIT: Just ran a check with aswMBR, here is the log for that as well.