A strange thing happened to me today. I don't know how to interprete the following situation:
I have two PC's (PIII and PIV), with Nvidia Vanta and AtiRadeon 9200 graphic cards. I'm running Kubuntu Edgy currently. In the afternoon I switched off my PIII, then after few hours trying to turn it on encountered an error. My display changed into 600x480 with 60 Hz. Tried to edit the xorg.conf...Nothing, even lost the X access. I got an idea, what about to copy the xorg.conf from another PC and overwrite the spoiled one. I went to the other, and turn it on. What a surprise! The display went away on this machine too. I reconfigured the xserver-xorg and saved the system. Now it's everything O.K. but I don't know what caused the problem, since the Kubuntus have been installed on totally different dates. Is it possibile to have some virus? How to check it? Have somebody encountered the same trouble? (Generally, not just on (K)Ubuntu)
Its not a virus. There are no active viruses for Linux and even if there were, its really difficult to infect a Linux system due to the Linux/Unix security model (unless you run as root all the time). Something is obviously messing up your settings. Have you done an upgrade recently?
I don't know exactly. I can only remember that I have changed the time monitor would be turned off in System Settings at both of the machines. In /etc/X11 there were two xorg.conf files, actually xorg.conf and xorg.conf.1. Since reconfiguration everything works fine, and I hope It will in future.
Something similar happens for my Fedora box... When I configure the resolution (or whatever change to the display options), the configuration tool sets the wrong display resolution/sync parameters. When configuring the display with nvidia configuration tool, everything is OK.
The morale is:
When you let a tool to modify your configuration, you may expect unexpectedly wrong results after X server restart.