Problems with the default settings

I don't know that particular thin client workstation but from the sound of it. it's very similar to others I have worked with. I suspect that some configuration data has got corrupted. There is normally a way to reset the terminal to the factory default - I would suggest you try that & then set it up again. It's a nuisance but I often used to find that was the only way to deal with this kind of problem. To reset it this way: There is often a small button on the back of the device which you keep pressed in whilst powering it on; if not you'll need to check the manual.