ROUND ROCK, Texas (AP) ¿ Computer maker Dell Inc. said Friday that Ross Perot Jr., son of former presidential candidate Ross Perot Sr. and chairman of Perot Systems Corp. before Dell bought the company this year, will join its board. Dell said Perot will start immediately and stand for election by shareholders at the company's annual meeting next year. Dell agreed to acquire Perot Systems, a technology services company founded by Perot Sr., in September for $3.9 billion. The deal closed Nov. 3. Dell shares rose 8 cents to $13.54 in midday trading.