DavidR
4
Unfortunately that doesn’t help and there is no way to confirm one way or another what it was without being able to either scan again or upload to multi-engine scanner.
If avast hasn’t found it again, it could be because it is hidden by something else. Was this detected in the first scan after installation, a boot-time scan ?
If so try that again if you didn’t try that. Right click the avast icon, select Start avast! Antivirus, Menu, ‘Schedule boot-time scan…’ that will run a scan before windows starts but only for the next boot (it doesn’t happen each time).
If you haven’t already got this software (freeware), download, install, update and run it, preferably in safe mode.
Ewido, a.k.a. avg anti-spyware or a-Squared free.