Yes you can easily create backup of your gmail account to your local hard drive in this process you need to install any email client to your desktop and let them sync with your email server, or if you don't want to install any client so in this case you need to use google free service google take out which little difficult and time taking process here is an another way to download backup is to use any third party tool try this if you want to save your whole backup in your local drive securely :- http://www.toolsbaer.com/gmail-backup/