What happens if you keep the native (recommended) resolution for all monitors. Do you have the same problem?
The card is a Appian Graphics Rushmore card. Could it be a bad driver if everything worked fine before switching the monitor? What is the equipment profile? Thanks.
Try your other 17" in the top position. Try a 19" in the top position. If when you align the monitor icons side-by-side and all is OK... then the problem is either Windows or the Appian driver. If there is no updated driver, then I think you are stuck.
If I set the resolution to the recommended 1280x1024 for all monitors it works fine (I see the full screen on all four screens) except when I apply the arrangement of the monitors in Windows Display Properties it rearranges the monitors so that they are all in a row (whereas I have one monitor above the center three monitors).
Did you try dragging the one monitor icon to the top position like the monitors are arranged... then save and reboot?
I have just followed what you have said on my Matrox G450 Quad. Look the screenshot, especially the bottom right where the screen configuration is. Is this what you are trying to do?
I have just followed what you have said on my Matrox G450 Quad. Look the screenshot, especially the bottom right where the screen configuration is. Is this what you are trying to do?
If it works on this G450 quad but not for twinpeaks, then the problem must be with the Appian driver and card.