Hello
Thanks to both of you for answering.
My only Av for years has been Avast. I uninstalled it last night after
- restoring from a 2 days old backup => no more problem
- upgrading again avast to new version => problem again
- uninstalling avast again in safe mode with avast uninstall tool => no more problem
- downloading, re-installing, re-registering Avast => shutdown problem
- chkdsk, Malwarebytes aso => computer OK
- complete scan with Avast (new version) no virus detected.
So, I suspect Avast (upgrade) to be related with the problem. Il kept it and power off manually my computer, but does not seem very clean
To be complete : I'm running SP3
Only tried 5 or 6 shutdowns
Firewall : Look'n Stop ... never interfered before.
Running in the background : Spybot Search and Destroy...
But all this for years now
Ideas please ?
Sincerely
B