Yeah the '301 KEYBOARD ERROR PRESS F1 TO CONTINUE' is rather stupid and redundant.
There's another Windows 3.x favorite:
"An Error has occurred in your application, if you choose ignore, you should save your work in a new file. if you choose Close, your application will terminate"
Either way the end result is usually a General Protection Fault, even if you choose ignore (and you usually get the same ignore/close prompt many times until you get the GPF either way, a bit like a windows version of Abort/Retry/Fail)
And who could forget these?
Mac OS:
Who said Macs never crash again?! and i think they were more cryptic than Windows errors.