A jury has convicted the WalMart Stalker of attempted rape.    34-year-old Seth Griffith of Norristown was also found guilty of trespassing, burglary, unlawful restraint and other charges.   Investigators say he followed a female college student home from the WalMart in Lower Providence Township last July and attacked her.   Griffith told the court the young woman had smiled at him in the store and tugged at her clothing in a way that lead him to believe she was interested in him.   He fled after the incident and was arrested in Nevada about two weeks after the attack.