Oil Paint is highly dependent on the video card, and usually when it fails that indicates a problem with the video card driver.
I backed out to the previous driver level - still no joy. It's not the best software behavior to not display any sort of message pointing to the cause or at least confirming it's detected a problem. (Speaking as a computer engineer with 30+ years of complex software system design experience.)
Not sure I want to go further backward in drivers. Where do I go from here?
Video drivers are like that - sometimes they don't give errors, they just draw incorrectly or fail to give a result.
Go to the GPU maker's website (nvidia) and install the latest driver. If that doesn't work, then you'll need to work with Nvidia to figure out why the driver is not working correctly on your system.