Hello all,
Problems solved on my side.
The next morning, Computer #1 had automatically updated to the latest version.
But strangely enough, Computer #2 (identical system configuration) didn't do anything.... Checked for malware again and found some. Deleted them. Then read new messages here and applied this instruction :
(Another option might be to go into the Control Panel / Add/Remove Programs, select avast! Antivirus --> Change/Remove and use the Update option - but that updates the program to the latest version as well, not just the virus definitions.)
It worked ;o)
Thanks for helping.
Sylvie