Needs help harddrive wil load up on one pc but not the other

ok my harddrive works when i hook it up to my laptop but when i moves it to my desktop (where it worked last week) it askes for the password i puts that in it unlocks but then it dont show up . 

the harddrive works when i hook it up to any vista pc but when i try and hook it up to my pc pc it wont load