i had a similar problem with Win64:Sirefef-A[Trj], and used ComboFix.
Can someone please have a look at the log file and tell if there has to be done mor to get rid of the probelm.
Until now, no more pop-ups of avast on my pc.
Here are additional info from malwarebytes and aswMBR.exe.
[*]Hold down the Windows key + R on your keyboard. This will display the Run dialogue box
[*]In the Run box, type in ComboFix /Uninstall(Notice the space between the “x” and “/”) then click OK