Why do the apps on my Iphone 4 crash and my phone restart?

So my Iphone 4 keeps crashing apps, and even sometimes it will even close an app and then show the silver apple symbol and then goes to the lock screen and i have to start over.

I have tried turning it off, restarting it, i haven't tried setting back to factory settings because i don't know what that does. Does it delete everything or what. Also i got a new system update for it a while back but i don't think thats what's caused it. I have also plugged it in to my computer and did some stuff while it was syncing and then disconnected it before it was done. I don't know someone help

Sounds like its jailbroke with evasion