use syncback, it is a free software and can do what you need and a bunch more. You can even schedule it to do the copy when no one is at the business.
I use syncback free and syncback SE to run automated backups of many of my clients work pcs to backup their files to their server, and to backup the network drive to a seperate drive.
The SE version of the program (only $35) can do FTPS and SFTP transfers over a network if you have remote sites, and does versioning (will retain pervious versions of the file in case of accidental deletion or accidental modificaion).
If you have all of your data on just one hard drive then you are asking for a failure. If that one drive goes bad, or the partition or file table gets corrupted then poof all of your data is now gone.