I have the same problem for weeks now. I have been infected when surfing on free streaming websites.
I use avast which first detected a rootkit and several malware and adware which infected my browser. Avast failed to clean things, so I did it manually.
I have several infections localized in windows\temp, Program Files, User\AppData\Local or Roaming, etc. Infected copies of firefox or chrome where installed in my programs.
I also had SSD filing, which was due to an inactivation of system restoration, and this allocated memory was filled up with I don't know what.
Now, I can cleanup everything in a few minutes, but almost every day, the virus (which one ?) reactivate itself, reinstall everything (BIT, reozerph, firefox, Wsnare...), and crash avast.
I am getting tired of it, and consider formating my computer. But if someone have the solution...