HTC EVO 4G :: Phone Won't Turn On After Initial Boot / How To Fix?

First the camera button is unresponsive, and now after owning this phone for about a month, I'm at my wits end! Has anyone experienced this? Last night after leaving the movie theater I pulled my EVO out of my pocket and pressed the power button - the bottom row button lights come on, but the screen does not (battery is nearly full by the way). Pressing the power button makes the bottom buttons turn on and off, but the screen is off. I perform a battery pull, everything seems fine, I can get into the phone after it boots, but once I press the power button to turn the screen off, the screen never turns on again - but the bottom buttons light up like last time. Repeat, repeat, repeat. I have to perform a battery pull every time I turn the screen off. I've now changed the display timeout to 'never' - and if I keep the screen on permanently from the initial bootup, the phone works fine. Absolutely insane. If Sprint can't exchange the phone (due to lack of stock) I'm considering going back to a blackberry. This is my third EVO, and although I love it when it works, I need something a little more reliable.