Display issue at Narwhal upgrade

[verrac]

Hi world
I just upgraded to Narwhal. On first boot I had a message stating my harware is not OK for Unity.
I found how to select classical Ubuntu, but I have the same flickering windows when I log in.
I must log in each time changing to "Ubuntu classic (without effets)" to get a usable desktop.

My laptop is a fujitsu siemens amilo 7405 with intel 855 video

Please how to get Unity or classic or classic w/o effects set as a default so that I don't need to change on each loggin

Thank you
-- Byb