Thanks for your reply. Here are the results in the order of tests.
- Log off by pressing Alt+F4 and selecting Sign off -> similar symptoms as described, but not exactly. If I wait, explorer finally arrives. Restarting the computer does'nt fix either. It's still a bit longer than usual. Reinstalling nvidia driver fixes the problem.
- Log off from the start menu : I understand by classic shell -> it fails as described in my first post. I had a doubt because Alt+F4 partially works, so I wondered if waiting could be the solution but no.
- Log off by pressing the user picture in the Metro screen. Didn't knew this way, thanks ! -> I had to switch off classic shell to run Metro. It's seems to be the same symptoms as Alt+F4, altough I had cases with no recovery of the desktop.
- Log off by ctrl+alt+suppr (not asked, but it's the way I did for my first post) -> oh no I feel I'm crasy ! I'm sure there were no problem (as I said in my first post) and now it fails too
By the way, trying the previous methods fails all the time now. It's as everything is getting worse ! But in a certain way it's good for you since it may not be Classic Shell...
- Log off by running "shutdown /l" from the command line -> same as the now unique symptom : fails.
Well, it sounds like I disturbed you for nothing ! Sorry about that.
Or if there where something to find, I won't be able to do so...
Thanks
renArD