I run ubuntu on my grandparents computer (they start xubuntu mostly, but kubuntu-desktop is installed as well). Earlier today I upgraded it to jaunty for them, the upgrade went fine. Since I don't have physical access to the box myself I did it trought ssh by editing sources.list manually and running aptitude -t jaunty dist-upgrade.
After the upgrade completed I called my grandfather and rebooted the box while he was sitting in front of it. He said that the boot progress bar showed up, but after that the monitor turned blank. The monitor went into power saving mode because there was no signal to it. I figured that it was a video mode problem, so I checked his xorg.conf and the xorg log file trought ssh, but everything seemed fine.
I then asked him to switch to a virtual console by pressing ctrl+alt+f1, but nothing happened. I tried other random things like restarting kdm, but he saw no reaction on the screen. When I rebooted the screen a second time he did not mention seeing the shutdown progress bar, I didn't specifically ask him about it, but he mentioned every little detail he saw so I think he would have mentioned that too if he saw it, so I don't think he could see that either. But when the box came back up again after the second reboot he did see the start progress bar, until the same thing happened again, the monitor turned on power saving mode.
I'm at a loss as to what to try next. Any suggestions?