The hard drive can be located under the front right corner of the laptop. Since the unit is upside down, the drive should be in the front left hand corner.

Two ribbon cables will have to be disconnected and moved out of the way to get to the hard drive. You can use a plastic spudger from previous steps to flip the black and white plastic tabs up, and then gently pull the ribbon cable out of the connectors, as pictured in the last two pictures here.

NOTE that for the orange colored cable, the top one here, the tab is black in color and flips up from the left.

NOTE that for the white and black colored cable, the bottom one here, the tab is white in color and flips up from the left.