I upgraded to iOS 5.1 a few months ago and I didn't have any problems with it until last month. Now, almost every time I use my iPhone for a for a long time, when I open up an app, it crashes and when I press on it again, it crashes again until my iPhone resprings or sometimes reboots and it takes 5-10 minutes to start up again. It doesn't happen all the time but it happens frequently as I said in the title. Sometimes, even when I'm not using it, it still resprings/reboots on me. Anyone got a fix for this? Thanks in advance.