I have a funky system with an HD4350 card that is doing weird things. Following the steps outlined, after installing the user modes, Windows is defaulting to a non-displayable/non-workable resolution on Display1. I am only installing MAME and have no interest in the other user mode resolutions. Should my action be then to edit the 'user_modes.ini' file removing the non-Desktop user modes resolutions before installing the user modes? Hoping by doing that, the non-displayable/non-workable resolution is not installed.
Or is there another way where after installing the user modes, I can force '640 x 480 @ 30.000000 desktop' on Display1?
Bueller.............? Bueller.............? Bueller.............? Bueller.............?
I don't know if you ever figured this out.
Without more information, the way I'd proceed is to use another monitor (a normal LCD or CRT PC monitor) where you have a workable picture, then use Arcade OSD to target the monitor you're going to use for emulation and force the proper resolution on it.
If the problem is you're already using a PC monitor and you get a garbled picture on it after installing the user modes, making it impossible to accomplish my suggestion above, then simply swap cables: maybe it's outputting 15 kHz to the wrong output.
I can't deduce what the scenario is from reading your post.