Well I’ve posted a similar reply to another user before but I’ll outline the solution that worked for me again.

The aswrvt.sys driver isn’t digitally signed by microsoft and windows 7 doesn’t like it.

What works for me is:

Boot to safe mode advanced options the scroll down to “disable driver signature enforcement” and select that option.

If boot continues and is successful then you’ll need to either:

Permanently disable driver signature enforcement (although this lowers system security it’s still possible to run other software that warns if an unsigned file attempts to run).

or

Manually sign the Avast driver using a certificate that you created locally.

If the safe boot “driver signature enforcement” disabled works - post back here and I’ll ad more detail. In the meantime if you get up and running I’d suggest a safe mode boot followed by a disk check using the command

chkdsk /f /r

from the run dialog box (in safe mode).