Undated -- United Airlines can't seem to catch a break when it comes to its high-tech systems. Even as it continues trying to win back customers lost after computer glitches hit earlier this year, there was another computer outage yesterday. That latest problem delayed thousands of travelers -- and resulted in a new batch of embarrassment for the airline. The outage only lasted two hours -- but it held up a total of 636 of the more than 56-hundred United flights set for yesterday. It's United third major computer foul-up this year.