I've seen posts with similar problems. Freezes, makes calls on it's own, the icons get twitchy, opens the wrong one. The hardware buttons (Return, home, etc.) aren't working right either. I turned off the animations and it helped a little. I see instructions for "Factory Data Reset." What does it mean "Erase EVERYTHING?" Sounds scary. If I get a new phone, what comes with me on the memory card?
Steps Factory Reset below