A computer cannot run without a hard drive. Hard drives store all the data the computer needs to be up and running, like the operating system, commands, and executions. Program files are also stored on the drive and so are personal computer files.

It's very sensitive though. Inside the hard drive is a constantly spinning disc and if this is dropped or damaged in some way it can be irreversible. If something that's magnetic is put on it all the data can be erased.

Anywhere from a hundred to a thousand gigabytes of space are on hard drives. A thousand is called a terrabyte. It depends on what types of files the user has. If it's a photo collection or music they may only need a few hundred. Graphic designers will likely need much more.

An internal hard drive stays inside the computer, while the external type is stored outside. Internal ones are for the computer to run on, while external is more for extra storage space and backup. They can be hooked up by USB cord.

It's common for a hard drive to die after long term use. Some will last for years upon years, and others may burn out after only a couple years. Regardless, they need to be replaced every now and then. Be sure you have your data always backed up on something else.

A good way to take care of your hard drive is to perform maintenance every so often, such as defragmenting. This deletes old and obsolete file fragments that are cluttering up the drive and will free up space and memory.

They can also be reformatted, wiped of all data, to start over, but beware as this will erase any and all data you have stored on the drive.