How to replace laptop hard drives
1). Don't rush into replacing the hard drive before troubleshooting the problem. The first step to take when working on any laptop or notebook computer is to remove the battery. Even if the power button is well protected, like under the closed lid of the screen, it doesn't mean that the power might not come on due to a mechanical jolt or a short when you're working on the innards, so the best bet is to just get the battery out of there.
2). Laptop batteries generally require two actions to remove them. In this case, the lock is on the front edge of the case, and it slides to the side. After the lock is released, the battery slides back just an inch or so to release from the connector, after which it's lifted out and removed.
3). As we lift the lid over the hard drive, you can see the long plastic tube that serves both as a screw guide and as a mechanical support. It should be immediately apparent that the hard drive isn't going anywhere without the cage either being removed first or coming with it.
4). Closer inspection shows that this hard drive mounting system relies on the cage being attached to the hard drive before the hard drive is installed in the laptop. The only things that secure the hard drive and cage in the laptop are the power and data connector on one end, and a spring steel tab on this end.
5). Once the locking tab clears the stub projection that holds the hard drive cage in place, the end still has to be lifted up till it clears the bottom of the laptop. There's simply no room within the laptop bay to pull the hard drive back and disengage from the mating connector. One the cage clears the laptop; it takes a bit of force to pull the hard drive out on as shallow an angle as possible.
6). The first step in replacing the hard drive is removing the cage from the old drive, which is held in place with four screws. Make sure you note which way the cage goes on the old drive before you take it off, because it will need to be mounted on the new drive the same way, even though more than one orientation may be possible. You can see the corner of the new drive in the picture, in case you thought we only had one:-)
7). Once the replacement hard drive is mounted in the cage, the whole assembly can be reinstalled in the laptop. Again, keep the drive on as shallow an angle as possible, i.e. close to the bottom of the laptop, as you slide the pins into the connector. The close tolerances on the laptop bay usually make it impossible to mate the connector improperly.
8). If you worry about prying the drive against the connector when depressing the end of the cage so the tab clears the locking ear, you can hold the top edge of the cage out as you pry the tab in, as I'm doing here. Laptop hard drives aren't terribly rugged; they're so light and slim that I hate putting any more mechanical stress on them than I have to. Replacing laptop hard drives is a bit nerve racking for people who haven't done it before, but as long as you don't use an unreasonable amount of force, it should work out fine.
9). We replace the lid and use the long screw to reattach it to the bottom of the laptop. The emergency restore CD that comes with the laptop is used to reload all the software on the PC, but your data is gone unless you backed it up. The shiny circular thing is called a platter, on which the data is magnetically recorded and read by a read/write head on the end of the arm (currently in its park position away from the platter). The noise you here when your hard drive is operating is the arm swinging in and out over the surface of the platter, which spins under the read write head to provide access to all the usable locations on the drive.