Malwarebytes v5.3.4.202 component package 136.0.5312 released.
From MBAM 5.0:
Features and improvements
Added a quick way for users to submit feedback without needing a forum account
Other minor usability improvements across the interface
Issues fixed
Fixed Tray Menu positioning issues on some multi-monitor setups
For now the old netbook seems to be OK with Firefox and Midori - at least as far as posting to this forum. I suppose I'll keep it stashed away until it won't work at all.