Unable to access the pen drive contents

Hello,
everytime i insert a pen drive in my laptop for a moment it shows the files and then shows there are no files in the pen drive.i tried to even search by the name in the pen drive but it wont show anything.......if i insert the same pendrive in another laptop it very well shows all the files....also whenever i insert the pen drive a mseaage gets flashed as in trojen horse detected and then after few minutes symantec has removed trojecn horse as asecurity risk............i am not able to understand is this the problem with my laptop or the pen drive........i have windows vista..........plz help