Mac Pro 5.1 won't reset pram
Mac Pro mid 2010, 27in display starts with vertical strips, can't boot to diagnostics, can't reset pram, can't boot to recover or safe mode. When start button is held at start up eventually a flat long tone given then the chime tone but no change to stripped display.
Seems like USB keyboard not functioning in addition to display being sent bad video
Mac Pro, macOS High Sierra (10.13.3), 8 processor, factory 4 2gbyte Simms