united airlines yanks its fleet of 757s out of service to check on a potential computer glitch. >>> dominos erupt in libya, as a tsunami of political unrest washes across the middle east. >>> and best in show. how america's new top dog made >>> and best in show. how america's new top dog made history at westminster. captioning funded by cbs >>> good morning, everybody. thanks for joining us, i'm betty nguyen. if you're flying on a united airlines this morning you will want to call ahead. united has grounded its fleet of boeing 757s. 96 planes in all, to complete a maintenance check on the plane's computer. united says to expect delays and cancellations. michael herzenberg is in washington with more on this. good morning, michael. seems like passengers are going to have to pack some patience today. >> reporter: that's right, betty. you could say united airlines is being pro-active, and that it was remiss. whatever word you choose, passengers may wish they chose a different airline to fly this morning. some united airlines passengers