New ram issues 2gig upgrade

have sony viao running windows xp sp3
been using 2 256 chips 1 in each slot runs great bought 2 1g ram chips same configuration sodimm pc 2700 ddr 333mhz same as 256 already been using 1 gig work fine with 1 256 in second slot but when i install the second gig it freezes shortly after installed i checked system it sees 2g when installed and sees either 1 g chip by its self or paired with 256 chip it then once frozen goes to blue error screen an it says hardware problem or software problem ordered new 1 gig chips havent gotten them yet is there something diff about sony?