Portable computer having a hard disk drive mounted therein

A portable computer including a central processing unit, a monitor unit laying on said central processing unit and being mounted pivotally on said central processing unit, and a hard disk drive unit mounted in said central processing unit, said monitor unit being locked releasably on said central processing unit, the improvement comprising:

• said central processing unit having a generally rectangular storage chamber formed in an upper surface thereof, said storage chamber having a bottom wall and a side wall assembly which includes four side walls, said side wall assembly having two locking holes formed therein, said hard disk drive unit including a sealed housing, a driving device disposed in said housing, two insertion elements mounted movably in said housing and extending from said housing to engage within said locking holes of said central processing unit so as to retain said hard disk drive unit within said storage chamber, a rotary actuating unit pivoted operatively to said housing and actuatable so as to move said insertion elements to retract into said housing, and a spring unit biasing said insertion elements to extend from said housing to engage within said locking holes of said central processing unit, whereby, in a case where said monitor unit is rotated away from said central processing unit, said rotary actuating unit can be rotated so as to retract said insertion elements into the housing, thereby enabling said hard disk drive unit to be removed from said central processing unit.