The specificness and uniqueness of my problem has made it difficult to find a solution through searches so now I have to create my own post on the problem: My iPhone 3GS that I got from a third party has had the problem of randomly shutting off at any given moment. I could be in the middle of a text, a call, or listening to music and it'll just shut off. Now here's the unique part. When I go to turn it back on, the apple loading screen pops up but it takes somewhere from 3-5 minutes for it to boot up. Then the lock screen with the time and whatnot shows up. From this point on, my iPhone has a chance to shut itself back down and I have to repeat the process over and over again. Most of the time the lock screen flashes and then goes straight to black (shut down) but sometimes I can make it a few menus before it shuts itself down. The only surefire way to keep the iPhone on is to plug it into a charger of any sort. I'm fairly certain it isn't a battery charge issue because this happens at any % of power and sometimes my iPhone can use up all of its charge and not have this happen while other times I can be at 90-100% and it could randomly shut itself down. My question is, has anyone else had this problem before? I'm hoping the fix isn't a hardware issue because this thing isn't under any warranties. Also, this problem has persisted through multiple firmwares so it isn't a firmware issue.