No video output after boot.

I've tried booting lucid with 2.6.31 kernel and Nvidia drivers (instead of 2.6.32) and the screen worked. I've also tried Debian squeeze with 2.6.32 kernel but with nv drivers and the bug didn't show up. I know debian kernel and ubuntu kernel are slightly different so what is the next step to tracking down this bug?
Later I'm going to boot ubuntu 2.6.32 kernel with nv (or noveau) drivers but I don't know what log/information are helpful to solve this bug can someone give me a hint?

Some news:
I've tried Ubuntu's 2.6.32 with nouveau driver and it works even if the screen resolution is incorrect. When I restart X with Nvidia drivers the screen turn off and the computer dies... even the Magic SysRq doesn't work, the only way to restart the machine is an hard reset which mdadm doesn't like it very much.

I've tried with a brand new installation of ubuntu lucid:
With nvidia drivers (installed with graphical menu) I got the same problem (system freeze and no video output)
With nv and nouveau it works well. How can I get some log/crash report from nvidia drivers?

Same issue with me. It was working fine, then I transported box to another location, set it up and when it boots up it mounts the drives and everything seems to be going fine, then, boom - video signal drops out. Funny thing is, when I press the reset button on the box, for a split second I'll see the kubuntu log in screen before the box restarts. Weird...

Not enough information has been provided to troubleshoot. See http://wiki.ubuntu.com/X/Reporting for instructions on reporting X issues.