Pavilion dv4 1431us how to remove the hard drive. Don't know which section is the hard drive screw to unscrew.

The Battery Compartment Cover is to the outside.
(By the way. Have all power sources removed from the laptop. The AC adapter {Charger}, and the Battery)

Laptop upside down, face the Battery Compartment to the top.
The long middle cover in the middle, under the Battery Compartment Cover is the Harddrive Compartment Cover.

On the Left side of the Harddrive Compartment Cover are two screws to remove. One in each outside corner.
After the screws are removed, lift up on the Left side to remove the cover.
(They may just loosen to a loosened state, and not actually remove)

The Harddrive Compartment Cover is 'hinged' on the right side, with a couple of plastic tabs coming from the cover itself. After it is tilted up far enough so that these tabs will come free from the slots they're in, the cover can be removed.

There are 3 screws which hold the Harddrive Caddy in place. (The Harddrive is mounted to a sheet metal Caddy, which goes across the top of the Harddrive, and down each side)

The first screw is in the Middle to the Left outside.
The other two screws are on the Right, and are on the corners.

After removing the screws you will see a Black strip of cloth/plastic coming from the Left side of the Harddrive/Caddy combo.

The Harddrive is eased up slightly on the Left side, and pulled to the Left side with the strip of cloth/plastic.
(On the Right side of the Harddrive is the interface. The pins that come out of the Harddrive. These pins insert into a female socket in the laptop)

The Caddy around the Harddrive is mounted to the Harddrive with 4 screws.
Two on EACH side.
Holding the Harddrive in the direction it came out of the laptop, (Interface pins to the Right), look at the mounting screw on the Right side.
The one that goes through the sheet metal Caddy, and fastens it to the Harddrive.

Now look at the same screw on the Left side. It goes through a tab.
Remove these screws, and DON'T loose them, or mix them up with the other screws.
(Use a multi-compartment container. You can use a clean egg carton in a pinch)

Remove the screws from the other side.
Install the new harddrive in the Caddy, then install the Harddrive/Caddy assembly in the laptop.
DO NOT overtighten the screws.

Regards,
joecoolvette