You have a rootkit infection. These are normally very well hidden and if non of the scanners know what to look for they will miss it.
Combofix has been good at a lot of these, but only supports Windows 7 and older, you didnt tell me what version of Windows you are on.
Then the scanners are always updating, after all they play catch up to all the new infections. So running malwarebytes anti rootkit, adwcleaner and so on all over again would be a good idea, and to run them from safe mode with networking.
But the only way you can be 100% sure that you are clean with something like this is to do a fresh reinstall of Windows. Not something a lot of people want to do, but isnt as bad as you may think.
Now normally when a customer brings a computer to me like this I trace and see what programs have access to the net and trace down where the infection is at. I have been seeing some new infections that are infecting the windows system files themselves and because of that most scanners wont touch the windows system files and so a lot of scanners skip it.
I have been manually finding and cleaning some new infections over the last few weeks that not a single scanner was finding but I was able to find manually. It will be only a matter of time before the scanners catch up and start detecting it, but that doesnt do any good now.
There have also been mast boot record viruses that even reinstalling windows doesnt fix it, because it is on the MBR of the drive. So anytime I reinstall Windows fresh I have the windows setup destroy the file system and make it new, thus making sure the drive gets the MBR wiped and remade.
Right now it is hard to tell what you have, but you are infected, that is for sure. So lets see what we can find, so what version of Windows? When was the last time you ran the scanners? And when you ran them did you run them in safe mode with networking and make sure they could update themselves?
Shane