I am not able to backup apps fromsettings menu. please suggest me some options..

[WPCentral Question]

I am using Lumia 625. my phone lags a lot. Am not able to open a few apps including storage sense and market place. as soon as I tap the app screen flashes to the same page again. I need to give a hard reset to my cell. But I need to make sure I am backing up my stuff. please guys suggest me some ways. and where does the whatsapp backup reside in my cell..