I have an HTC Desire 520

[AC Question]

The camera goes back off in just a few seconds. It just goes back to my home page. I cannot keep it on and I think I've tried everything

 

[B. Diddy]

Welcome to Android Central! Try booting into Safe Mode, which temporarily disables all 3rd party apps. How to turn on safe mode on Htc Desire 510

If the problem disappears in Safe Mode, then something you installed is causing the problem. You may have to uninstall apps one by one until the problem disappears. If the problem persists in Safe Mode, then it's more likely to be a hardware or firmware problem.