can't see Nvidia startup logo

[how]

can't see Nvidia statup logo. black screen

[azerty]

Try disabling AGP. You have to put
Option "NvAGP" "0"
in the device section in your XF86Config file, (the same section where you have changed nv by nvidia).

[how]

disabled AGP made no change.
I

[azerty]

So you don't have the same problem as me, i can't help you. try to find out the cause of the problem by looking at the XFree.x.log file placed in /var/log after a failed startx