I had a similar Problem, that actually came about from an Email from Gmail, traced back to China. I have been watching this Thread, wasn't sure until you mentioned Gmail.
If it is the same? it is a devilish thing, that really freaked me out.
It could not be detected in any other way, except for the Fact that it was generating so many copies of Files? Over ten Copies each of my entire C:/ Drive. At one stage I had nine Computers completely down from it. I don't have a "Quick Fix", but I am happy to share what I did to try to resolve it.
BTW, I am working on the fourth one to come back online, during the time I also had serious Medical Problems.
Louis/hamluis is corect, the thing I had actually took out HJT and turned it into a Zombie, bombarding me with Spam as it did with many other Programs, bombarded my Windows Live Messenger List and also every one that I had sent an email to through Outlook Express. I do not use Outlook Express or IE6 in any way now, yet keep them up to date, same as Windows Live or Messenger, which I access for emails only from online, no input is allowed beside that.
You could try a Free Program, called Threatfire? It works similar to TeaTimer from SpyBot S&D, but without the Resources grab. It just tells you simply when something, "Maybe" Malious is trying to alter your Computer and gives you an option to block it. That may Help? It's Scan actually counts the number of Files scanned and displays them.
http://www.threatfire.com/download/Ray.
Edited by Drovers Dog, 16 April 2010 - 11:06 PM.