My solution(s) were a bit more complicated, but mine are also back.
I started last night by running Firefox (FF) in safe mode thinking that an add-on was causing the problem, but I had the same result, "black screen - An error occurred". Then on a hunch I disabled flash and Derek's video ran, but IE10 still didn't.
I had seen LaybackBear's (LB) post were his came back after hibernating over night and I re-enabled flash and the video was still working, but IE10 still didn't.
After looking through my IE10 settings, I saw that active-x filtering was turned on so, I turned it off and the video ran.
I believe the FF problem was related to youtube's servers being down,
a belief I posted over on jumanji's thread. Seems
Downdetector was showing youtube was having problems since March 5th, and the IE10 fix is self-explanatory.
I'm still wondering why the video worked after disabling flash on FF while youtube was still having problems, and why everyone else was able to see the video while LB and I couldn't. I'd of loved to have found the active-x switch during this troubleshooting.
EDIT:
There's been an update to jumanji's thread by z3r.