Why does my iPhone 4 crash randomly?
Recently, over the past couple of weeks or so, my iPhone has started crashing very often. It happens on every app - the camera won't load, safari crashes regularly and games such as Draw Something won't even run. I've tried deleting apps, pictures and videos to make room, but that hasn't had any effect. I've tried closing apps that are open (double clicking the home button and swiping up on the apps) but that hasn't done anything either. I'm not sure if it's because of iOS 7 - it was fine to begin with and there have only recently been problems.
I've made sure everything unnecessary (e.g Bluetooth, etc) is off. Is it possibly a virus? If so, how do I check for one and get rid of it?
Everything is slow, and I don't know how to fix it or to stop it from happening. Any ideas?