>* starting application by double-clicking on program icon rather than shortcut yields same result
>* started program from command line to see if there was any output on console -- nope.
>* Made sure computer wasn't configured for secondary monitor (with the secondary disconnected) -- ran across that once before.
>* disabled hardware acceleration (I've seen this affect it) -- no change.
>* normal DPI settings (have come across weird stuff whenever you fiddle with DPI settings).
>* fonts required by application are indeed installed.
>* double-checked to make sure proper foxw2600.esl is loaded (renaming the existing copy resulted in expected "cannot find foxpro runtime" error message).
>* checked for extra CONFIG.FPW -- no extra ones found that would account for this behavior
>* it did not appear that the desktop theme was customized.
>* no funky resolution selected -- was set to 1024x768

Did you check that the video driver is exactly correct for the hardware?

One relatively easy thing to try would be using the plain-Jane 640x480 VGA or 800x600 SVGA modes. Or, maybe even try running the app while in Safe mode.

If I haven't already mentioned AV, it would be worth turning off real-time scanning for testing.

Could it be a permissions issue? Is the user an admin on their local machine? Does the (if specified) temp file folder exist, and does the user have permission to access it? Is the temp file folder full of orphaned files?

Any other unusual software running on the problem machine? I'm thinking of utilities that work directly with the display, such as SnagIt, but there could be others, too. It might be interesting to have ProcessExplorer running while you start the app, to see if any other processes or DLLs activate unexpectedly.

Maybe you could compare the WOW-related registry entries on the problem machine with one that is working OK.