MBR:Backboot-G[Rtk]

MBR:Backboot-G[Rtk] is detectected every time free antivirus is run.

None of the options removes it.

It is causing unwanted pop-up windows SUCH AS:
"There was a problem starting C:\Windows\yqhmvzmokepdlj.yqy
The specified module could not be found

Is there any solution?

Start a topic in V&W and post your logs there: https://forum.avast.com/index.php?action=post;board=4
Instructions (basic diagnostic logs): https://forum.avast.com/index.php?topic=194892.0