PC After scan Error

[tickpop]

Full Virus Scan;
Result;
 MPPT97:ShellCode-O [Expl]       (in red "Error")
 
  Win32.Malware-O[Expl]           (in red "Error")

Suggested send to "Virus Chest" but there was no button to click for "Virus Chest"

What did ERROR mean ?

Next day, after running 5 hours;  Win32.Malware-O[Expl]           (in red "Error")

Apparently Avast didn't remove it

Have screenshots

[rocksteady]

You may be better off creating a post in the Virus and Worms section here:
https://forum.avast.com/index.php?board=4.0

If you have screenshots (as you say), use the "Attachments and other options" link below the text box to add them to your post.