I recently played a game where i made my move and the clock changed over showing my opponents time running down after waiting for about 4 minutes his clock reached zero and it shows i lost on time. Can someone tell me why

I don't know why, but it has happened to me as well

It is a big pain in the butt, cost me a game

Just happened to me a few minutes ago.  His / her clock was red, running down, I couldn't move.  I had 3+ minutes left.  I lost on time.   What gives?  He would have won anyway, he had a huge advantage.

Barnyard

Yes the same thing happened to me when I was in an overwhelmingly winning position.  The opponents clock drained away without him moving  and I was deemed to have lost.  Computers!!!!

Now just an idea here, guessing... looking for a reason... could it be my computer just did not refresh?  Only thing wrong with that theory is the clock was still ticking down.