You need to back up your Payroll company file on a regular basis. If your computer is lost, stolen, or damaged, your backup is the only copy of your information you'll have to restore your company file.
Save your backups to external storage, like a USB stick or an external hard drive, and store the back up separately to your computer. It's a good idea to store your backup offsite or in a fire-proof safe.
For backups saved on external storage devices, you should check them now and again (by restoring the backup) to ensure they still work.