[techhelpbb]

You need to edit xorg.conf and force it to use the proper driver and video modes if xorgwizard is configuring your monitor in a way that is not practical for you. Odds are that your hardware is returning a list of video modes that includes some that are really not a great idea and every attempt X-Windows makes (on each distro you've tried) returns the higher resolution so it figures that makes the best sense to use. You need to inform it otherwise. This actually happens often but usually you can either get into text mode to force it to stop or navigate in the GUI to lower the resolution to something workable. Changes to the login pages or otherwise sometimes require additional tweaks. This used to happen quite often with incorrect DDC (display data channel) information exchanged between the monitors (in your case probably integrated into the system) and the video subsystem. This can easily be made worse with the complexity of various Linux video card drivers, combinations of displays and video subsystems and system chipset issues.

If I have a few minutes I will toss a copy of PuppyLinux (or whatever distro you actually would prefer to use) into a virtual machine and see if I can't give you an example or some instruction. I am swamped right now so it might not be today.

It would help if you could provide the make and model of the thin client hardware you are messing with and specify a Linux distro you actually would prefer to use if the display would work correctly for you. That way I can figure out what sort of video chipset is probably integrated into it and what needs to be done. Given your display is 640x480 I suspect there is a very good chance I can make this work but generic instructions would be painful because of subtle differences.