You have two broad options for maintaining copies of your files online: cloud backup services and cloud storage services. That backup plan also comes in handy if your computer and external drive are both damaged by a power surge or malware.

That way, if a natural disaster wipes out your computer and external hard drive, you can restore your files using an off-site service. The three places are typically a computer, an external hard drive, and a cloud service. 'The best advice around backup is to have it in three different places,' says Sean Metcalf, founder and chief technical officer of Trimarc Security, a company in Washington, D.C., that helps organizations secure their Microsoft platforms. Another option is to store them in the cloud, which is made up of remote servers you access online. But even backing up files to an external hard drive on your desk isn't always enough. If you've ever accidentally deleted or overwritten an important file, spilled a cup of coffee on your computer, or had a laptop that was lost or stolen, you understand the importance of backing up important files.

Personal computer backup services