How to Add a New Hard Drive to Your Computer in 8 Steps

4: Buy a new hard drive

You can buy a new hard drive from many different places: a retail store, a large computer store, a local computer parts store or by mail order. Wherever you go to buy it buy it, keep three things in mind:

Buy a "normal" 3.5-inch wide hard drive. They're sold everywhere, but you want to avoid the smaller hard disk drives made for laptops.
Make sure the new drive has the correct cable system (SATA or PATA) to match your machine.
Make sure the drive is big. Buy the biggest drive you can afford, because it will probably fill up before you know it.

Now that you have your new drive, you are ready to install it.