As we've discussed, freeing up space on your hard drive is great for your computer's health—but an external hard drive isn't the only solution. If you'd like to avoid adding another gadget to your life, and you have some DIY expertise, you can install a second internal hard drive in your computer. This is a more technical and time-consuming process, but it creates a more streamlined look.
Before you dive in, be aware of a couple caveats. First, any time you're messing around with your hardware, you need to safely back up your data before you start. Next, this process won't work on all computers. You'll need a device with a second drive bay, so that rules out laptops and all-in-one machines like Apple's iMacs. If do you own that type of computer, you might be able to replace the original hard drive with a more capacious one—but that process is much more difficult, so we're not including it in this roundup of easy upgrades. Last, you don't need to be an expert to add a second hard drive, but you should be comfortable with a screwdriver.
When you go shopping for your new internal hard drive, make extra sure that your choice is compatible with your computer's make and model. You can also look for installation guides that reference your specific device—for example, this one covers the Dell Inspiron 3650—to see which drives they recommend. As with external hard drives, you should also consider whether you'd prefer a slower HDD drive, such as Western Digital's 2TB Black drive ($110 on Amazon), or a faster and pricier SSD drive, such as Crucial's 2TB MX500 ($483 on Amazon).
Once you have your new drive, the installation process follows the same basic outline. Slip an anti-static strap onto your wrist to ground yourself, power down and unplug your computer, and open up the chassis. You should see an additional drive bay underneath the original drive, where the new hardware can slot in. Finally, you link up the cables for data and power. To see the type of connectors you need to look for, consult a tutorial video like this walkthrough from MasutaGaming or this one from KillerTech. Just be aware that you'll find slight variations in the components' design and layout, depending on the type of machine you own. For specifics, look up your computer's particular make and model.
Source : https://www.popsci.com/cheap-easy-computer-upgrades