black screen but no errors or warnings

[check3r]

Hi my Xserver starts without errors but the screen stays black.
Graphic Card: GT 425M
Ubuntu 11.04
I installed the newest driver manually from nvidia.com.
i already fixed these errors:

no devices detected => BusID "PCI:1:0:0"
no display devices found for this X screen => Option "ConnectedMonitor" "CRT"
unable to read edid from display device CRT-0 => Option "CustomEDID" "CRT-0:/etc/X11/edid.bin"

but now there are no more errors and the screen just stays black.
please help.