It's likely you timed out. Unless your opponent doesn't have sufficient material to checkmate you (in which case the result would be a draw), a time out will result in a loss no matter your material or positional advantage.
How did I loose a game?

The clock still had 4 minutes on it, so as the game progresses, does my time go down for each move? sorry for the stupid question, but I would really like to understand this rule.


Thanks for the info, I think I am starting to get it. Ok, cool Ill have to work on my timing. Thanks all for the great info.




The clock still had 4 minutes on it, so as the game progresses, does my time go down for each move? sorry for the stupid question, but I would really like to understand this rule.

PLay 'Live' chess if you want the pressure of a clock
Play 'Online' if you want to not worry about a clock
Best of luck!

Thanks again, I think I understand it now. So far, that is the only game I have lost due to time....
But one more question on time. Say I move along fairly quick, but my apponent moves slow, or sometimes veeeary slow. Will the game time out on them? Does the computer keep track of who is actually delaying a game?
You have all been very helpful, and I am very much enjoying the site.
-Tony

Say I move along fairly quick, but my apponent moves slow, or sometimes veeeary slow. Will the game time out on them?
If they use the total amount of time they were alloted for the game, then they would time out and lose, which is apparently what happened to you in this game.
Suppose you're playing a "15 minute" game. In chess that means each of you starts with 15 minutes on your clock. When it becomes your move your clock starts ticking down from where it stopped after your last move. As soon as you make you move (send it to the chess.com server), your clock stops at whatever point it had ticked down to and your opponent's clock starts ticking down from his most recent remaining time allowance. This goes on until the game ends by checkmate, draw, or resignation, OR until one of your clocks runs down to zero time left. If someone reaches a total of 15 minutes played for all his moves, he loses, even if he was in a much better position in the game.
The shorter the allowed game time, the more quickly time becomes a real pressure to the player-- when he knows he's getting down close to no time remaining he has to make his moves fast without being able to think very long. If one player has a lot of time left he can think about more possible moves, or do a better job calculating exchanges, or making sure he doesn't expose a piece to capture.
There are other factors that others have mentioned, such as time increments, and insufficient mating material, but a lot of basic timed games run as I've described.
I was in a good match, but I had the upper hand. A few more moves and it would have been over in my favor. Then the game ended, and showed my challenger the winner. I was clearly in the lead...How did this occure? I think it may have been a time issue, but would the end of the game not have been in my favor? I am just learning these time rules...
Thanks for anyones help