I did what you told me. Had some problems with avast, though. It’s my only antivirus/anti-spyware, and I deactivated it permanently (there are temporary options), but after the automatic restart made by by the combofix it gave an error, saying that avast was still active. There was no icon in the taskbar, so I opened the task manager and there was indeed an avast process running. I forced it to stop and continued with combofix, but it alerted me that it was still running. At this point I just didn’t know what else to do, so despite understanding that there was a risk, I continued with combofix anyway. It did its thing and now the computer seems to be running fine, I’ve been working for over an hour and there has been no alert from avast so far (before it gave me warnings every 5 minutes or so).
The log is attached to this post.