I recently received a Hewlett Packard Laptops model 15AC121DX. I am going to walk you through the memory replacement process. There are 12 total screws that you will need to remove from this bottom cover.
You can place this laptop face down. You need to take out the battery. There are two plastic releases that you need to use in order to remove this battery.
Once this battery is removed, you will notice two small screws under the battery. Remove these screws with a smaller phillips screwdriver. Now you can remove the other 10 larger laptop screws.
You will need a phillips screwdriver for those 10 screws as well. Once you remove those 10 screws you will want to remove the DVD optical drive. Once the optical drive is removed then you can go ahead and remove the bottom cover.
The easiest way to remove this bottom cover, is perhaps to place this laptop facing down. Now just pull up on the bottom cover. This cover should come off pretty easily, as long as you have removed all 12 screws.
There are two memory slots located in the center of this Hewlett Packard laptops model 15AC121DX right next to the microprocessor heat sink. In order to remove one or both memory modules, you just pull outwards on the two shiny metal releases. These memory modules will move up as long as the releases are pulled out.
Now you can just grab the memory module(s) by the end and pull them out of these slots. When you replace these memory modules make sure to slide them flush and tight so that you cannot really see any of the metal contacts. Then just push down with your fingers on the edges of these random access memory modules until they are in tight.
The two metal releases on each side will hold these memory modules in place. You have successfully replaced the memory on a Hewlett Packard laptops model 15AC121DX.