Think I figured it out, although avast uninstaller should have removed it all from a mac... its not microsoft windows.
have to cmd r then terminal, then scrutil disable, restart, trash folders, restart cmd r, terminal, csrutil enable restart cmd r to check csrutil status... restart.
But... like I said... avast should have removed it all with its uninstall app. I was going to subscribe to full software... but now I am going to sophos.