Humming Like a... What?!

OK, this is my last post for today. As some of you know, my laptop has been in the shop for a week because it contracted pneumonia (ever so much worse than a plain old virus). It's been very, very trying for me and, apparently, for the guy at the computer service place, too, as he's been sounding more and more frustrated every day that it's taken him a week to do a job he's only getting paid $75 for. He's got an accent that I'm pegging as eastern European, though he's obviously been in the US a long time (he's been in business here for 20+ years). It's clear, however, that English was not his first language. He called me a few minutes ago to tell my computer is (FINALLY) ready... he said (very proudly, too, I might add), "I've got it up and humming like a horse!" Like a... horse? Maybe he learned English from Mr. Ed? Dunno... but as long as 'humming like a horse' means it's (FINALLY) working, I don't give a crap!