Firefox "critical update" scam

So I was fooled by the Norton "critical update" tab popping up, and allowed it to run.  A program was downloaded, then the machine rebooted.  As that was happening I realized this had to be malware.  Norton did not stop anything from running, and did not detect any intrusion.  I searched for possible sources, and found info on the malware that pops up the window, but no info on fixing whatever got installed.  I followed instructions for removing the Kotver trojan, just in case - but it found nothing.  I deleted it anyway.  Overnight, Norton found unusually high traffic from this computer to the internet - so I ran Norton power eraser and removed a .lnk file that was suspect but could not be confirmed as malicious.  I ran Norton Utilities to assess any registry issues, then ran CCleaner to do the same thing, and deleted all temp files.  I uninstalled and reinstalled Firefox.  Last night I got the message again from Norton about unusual internet traffic, but Power Eraser found nothing.  Norton AntiVirus also stopped a web attack this morning.  So something is still going on with this machine and I have shut it down until I can find more info to clean it.  Does anyone know what gets installed if you fall for the fake critical update?  (Windows 7 64 bit)