Hi,
i found a solution to my problem ! :
1 i retry configuring my video card with the generic vesa driver and a 800*600 /60htz.
2 Test -> settings : OK. I have read in a forum that these are settings used for graphical install.
3 Install nvidia's driver 1.0-6111 as root with sh NVIDIA-Linux-x86-1.0-6111-pkg1.run
4 Edit my xf86config-4 with :
Section "Device", modify :
Driver "vesa" or Driver "nv" by Driver "nvidia"
Section "Module", add :
Load "glx"
Delete if exists :
Load "dri"
Load "GLcore"
5 Connect as user, startx and all works fine !
bye