Ray, I also have an older computer to run JMRI and Lokprogram on. In my case, it's a Dell XPS laptop. When new, it was top of the line, but that was 8+ years ago. I kept it on Win 7 until the first of this year when support for that OS ended, and upgraded to 10. That has brought on all manner of display issues such as you're describing. I finally wiped the drive, and installed Windows 8.1 on it, and the display problems stopped. It used the Win 10 license key stored on the motherboard to activate the older version. Windows 8.1 is still supported by Microsoft.Well....my computer problems continue. My main Win10 machine seems to have settled down, although I'm not totally certain. Did a Reset, but still had some issues, seems to have been OK today. Can't say the same for the mini tower I got to run JMRI on, seems to have died because of equally strange reasons. When trying to boot up the screen gets taken over by vertical columns of what look like hundreds of fine bars of military decorations, jiggling or flickering which also fades and obscures the background. Managed to make out the words run recovery I think, but was unable to do so through it. I had previously Uninstalled an AVAST anti virus program and secure browser program that Google had blocked as dangerous. At the time of doing that, subsequent boot up speed etc improved markedly. So it looks as though I had inadvertently installed a fake when originally looking for a free one when setting it up. Even the WIFI dongle was not flickering or even lit up..
Because the Win10 is about 8-9 years old now and started life as a Win7, I'm looking at a new one with the much improved i series intel CPU's. Present one is the first of the i3's and am told the latest version 10 of that is as fast as the original top of the line i7. Think I'll go for an SSD hard drive too. 8 Gb of RAM offered as well, instead of the current 4 for about $AU900. Whether it's even worth having the mini tower looked at with it's Pentium processor is moot. Was so handy as it fitted nicely inside the desk that also contained the 22" monitor all enclosed when not in use. A later model refurbished one I guess. I like a larger screen than is available in a Laptop.