Meet me in chat for real time support if you like. Also what version of the emulator are you running? What's the name of the exe file? From your first post, you're using the parameters for ePSXe emulator. PimpDaddyStu is on the right track.
I'm sure it has to do with filters. Filters can fine tune your list so if you have setup as an emulator, it will list every rom you have where as setup in MAME, it can filter out some games depending on your selection.
Best to start a new post when one is already resolved so that you don't get overlooked. Best thing is to just import the config for that emulator as it will have the setup used for mounting images. Here is the command-line for it based on mounting in GameEx according to the config: pce.exe "syscard3.pce"[-VIRTUALDRIVE-]
To answer your question, as far as updating to a newer version of MAME then it's recommended to update your romset as well so that you don't have errors and so they match. If your missing roms then you need to fill them in. We can not go into details about that since it's against forum rules so please don't talk about that here.
If you want 640x480 then FullMode should be equal to 0. Now it's set for 800x600 which you stated. The following will correct your issue: FullMode=0 FullScreenWidth and FullScreenHeight is the values for a custom resolution and those values aren't used unless FullMode is equal to 4. From the readme: The table below shows the settings: Fullscreen Resolution Ini SettingsFullMode=0640x480FullMode=1800x600FullMode=21024x768FullMode=31280x1024FullMode=4Custom (Set in .ini)In my first attempt, the values would not save to the ini from the GUI. They will be saved if closed by the window and not the close menu item. So this is how I discovered these values.
From my testing it seems that any changes that are made in the GUI are not saved in the ini. I had to make changes to the ini itself for the settings to stick.
Wow. I didn't even know that I had that site still. LOL. I had created to make a wiki but stopped the project. Will take it off and offer everything here so probably best not to link to it but thanks for pointing it out. Edit: Site has been removed. All content will be found on my post in the exception of this emulator. But the recommended command-line still is the same as well as use of my map file.
Use a power supply calculator to help determine the size needed. This is one I'm aware of that's recommended by fellow computer repair techs. But as mentioned the power supply you were using was way underpowered for that setup.
As far as other emulators with a different naming convention, I would take a look at Dat Workshop Pro. Toy with that and it can create dat files based on certain criteria.
And here you said that your folder listing did it correctly. LOL. Just edit the map file to list the way you want and you can leave your rom names intact. I sure wouldn't change them for the purpose of maintaining either. A few simple changes in a map file would be the way to go.
No-Intro dats can be tweaked via the website. You have options like filtering by language, region, etc. That would be the most simple way of filtering. There are other options as well depending on exactly what results you're after.
[VIRTUALDRIVE] is the parameter but how to use it depends on the emulator. Fastest way is to import the included configs. As they are already setup for this use. If not then post which emulator and we can troubleshoot. Also take a look at the help context and it will give some examples.
The old way still works but it can be used even easier now by a parameter in the command-line instead of using launch before/after. This just simplifies setting up emulators who need mounting and also frees up the launch before/after for other apps.