Blackberry 8310 Help?

So my Blackberry keeps turning off and doing a hard reset by itself. There are three ways this happens with my phone.

Scenario 1: (Started happening after Scenario 2, now happens almost everyday) I have it automatically turn on and when it does I can feel it vibrate from getting emails but I'm still sorta sleeping so when I fully wake up my phone isn't on anymore. Then, even though it's fully charged I have to plug in the charger then it turns back on, but it turns on like I took the battery out.

Scenario 2: (Used to happen alot, but Scenario 1 happens instead) My phone freezes when it turns on. It freezes when the AT&T and the globe thing pop up and I have to do a hard reset to turn it back on, Yet again though I have to charge it because it says I have no battery even though I do.

Scenario 3: (This just happened for the first time today a couple of hours after Scenario ! happened) I was listening to the music on my phone, I have a memory card, and I went to change the tone for my SMS messages and a hard reset occured.