just changed my 40GB HDD to 500GB..at first quite panic also as the blue screw badly damage and really tough to open (a lesson for me not to use bigger screwdriver and must rotate very gently)

brought to Bernard GS and he managed to open the main screw..then the rest I changed by myself and just pluck the blue screw in without rotating it..hope it will well attach (there's already four screws locking the HDD)