Looking OK.
I'm about to go to bed shortly. What I recommend is a scan with Avast (just the C drive) to see if any of those reg settings it alerted about before are detected.
Reg settings without the associated files are inert of themselves, so there is no big urgency. It is best to remove them, though, as they are likely to create startup/shutdown error messages similar to the one you reported earlier.
Here is a text I composed for posting earlier, then held off as a result of your "GAHHH" post. Since I'm going to be away for 8hr+ it should offer you some good guidance to work with. Others may post advice here too, this forum is good like that.
As Spiritsongs mentioned earlier, probably Oldtimer and Essexboy are the ones most qualified here to remove malware that is "tricky".
This is getting you to a workable state, though. So there's the caveat: I've been involved in helping users clean their computers with often apparent good results (depending on the infection) but I have no formal training.
What to do next?
Earlier YoKenny provided a link for Ccleaner slim. Grab that, and install it. Tick anything that has a "temp" in the name, including temporary internet files, and run it. An alternative to the (popular) Ccleaner is
ATFCleaner. I like this one for these purposes because (1) It's a small download, (2) it requires no installation and runs from the download location, (3) it is hard to damage your system using it. (If you try a bit you can bork your settings using Ccleaner.)
Check the Windows Security centre, and your Windows firewall is turned on. These can be accessed from the control panel. If you can't get the firewall on, or ascertain that it is on, skip the next step.
Check the Security Centre is actually working by pausing the Avast Standard shield very briefly. A red shield and warning should appear in the system tray. It should vanish when you resume the standard shield.
All good so far? Reboot the computer and run a quick scan with Avast.
Scan your external drive with MBAM, and maybe Avast also.
How's everything running?
Later:
Update your IE to IE8. This has been available for a while.
Go to
MS Update and have it check that you don't need any more updates that may be missing. Make sure Windows Update (access at Automatic Updates in the Security Centre from the control panel is set to either "automatic", "download" or "notify". If it's off, don't leave it off.
Have a look at some of these tutorials and info pages about security.
MajorGeeks (Lots of good info, appears not to have been updated in a while.)
SpywareInfo (ditto).
Consider getting and learning to use a 2 way firewall. I use
PCTools because it's fairly easy to use, and effective. The point of this is that if any malware tries to "phone home" the firewall should block it until you "OK" the prompt.
Consider installing
PSI by Secunia. Or at least use the online scan. This will alert to any out of date and vulnerable software you have installed, and provide a sensible toolkit to update same. You might be surprised.