How to swap hard drive for SSD in Asus D550CA-BH31?

Not to familiar with that model but with most PC laptops you must remove the screws from the bottom and also ones underneath the keyboard. Usually the keyboard pops out and has a flex cable you will need to unplug and it then exposes screw holding the top and bottom pars together.

Just wiggle the corners a little it will pop out. There are no other screws it just gets stuck in the middle.

I assume the D550CA-BH31 is essentially the same as the D550CA-RS31. After you take out the screws the keyboard is still attached by a number of plastic clips that ring the inside edge of the chassis.

For the RS31:

1 - Start by taking the 8 or 9 screws out of the bottom

2 - Pop the cover off the optical drive

3 - Open the screen

4 - With the drive cover off you can pull up on the top right corner of the keyboard, popping of the clips

5 - Work your way from the right side to the left side popping off clips on the top and bottom at about the same pace.

6 - 3 ribbon cables (power, keyboard, touch pad) are now all that connect the keyboard to the rest of the laptop. Disconnect them and you should be free to swap drives.

The keyboard seems a bit flimsy so be firm but gentle.