HTC EVO 4G :: Phone Working But Screen Black

HTC Evo was working fine, started noticing screen flickering but phone continued to work fine. Updated to froyo 2.2 and did sprint updates, phone still worked fine, then next day in the middle of playing with phone screen flickered and went black. Tried removing battery and rebooting several times but no luck. Left battery out overnight and tried again in the morning white htc screen appeared and then flickered out to black. did a hard reset, with the screen still black and still nothing. I've gone back to my phone after it has set for hours untouched and press the power button I can see the lock screen but it too goes away after a second or two. Phone is functioning lights at the bottom of the phone are lit and respond when I press them just no visible image. I don't have the insurance so I'll have to pay for all the fixes myself and I've had it since August so there is no returning it to the store. I've searched the web and I haven't seen a solution to what the problem could be is it the LCD screen or the motherboard. I'm ordering another screen but I'd hate to find out it is something else.