By what I can see in Task Manager, Geunfy.exe, Yurejjaeb.exe and sometimes Yjetipudl.exe just aren’t going away. These usually reappear within seconds if I try to end them, and Geunfy.exe is apparently running some service called Noije, which when I try to stop it, prompts me with an “Unable to stop service/The operation could not be completed/The requested control is not valid for this service” dialog.
I’m pretty sure I picked all this up somehow while visiting a keygen site yesterday. All of this descended on me at once a couple of minutes afterwards, at least from what I could observe.
Apparently part of this infection involved installing some garbage malware removal tool (I can't recall what it was named, sorry). First I uninstalled that and then allowed Group Policy to run Windows Defender again. I updated its definition list and removed whatever Defender could identify, and used Programs and Features to remove several other programs that had installed themselves. Apart from downloading that definition list update, I have kept my laptop disconnected from any network and have avoided opening any browsers. At this point, Defender thinks everything is clean and doesn’t seem to be of any further use, though Geunfy.exe is certainly still there and hogging a minimum of 70% of my CPU at the very least.