Where are thin client user video resolution settings stored on server?

I have an Edgy 6.10 Edubuntu thin client network running and have found a problem I could use some help on. I logged into a client as user "j" and changed the video resolution. I then tried to log into a different client that does not support the particular video resolution of the 1st. I cannot see the screen because the video resolution and frequency are not supported on this client. Therefore, I assume the user settings are stored on the server somewhere. How do I change the user settings on the server so I can correct for things like this? Any assistance is appreciated. Thanks Jim //not a networking question. moved to Linux - Server.  more