How full can you fill a hard drive

External hard drives are almost a commodity these days. They're cheap, come in multiple sizes, and they're pretty easy to find. Still, some are better than others: They're more reliable, more portable, have more connectivity options, and so. If you back up your hard drive, you can save yourself headaches in the future if you should lose your files. Learn how to back up your hard drive. Advertisement By: Josh Briggs Personal computers are perhaps the most significant invention. You'll need to replace a hard drive after a failure or to increase storage. Here's how to replace a hard drive in your desktop, laptop, or tablet. Tim Fisher has more than 30 years' of professional technology experience. He's been writing a.