Example UTFT sketches run for a few seconds then white screen

I'm a novice to start off. I've got a Mega 2560, a 3.2" touch ILI9341_16, and am using an Uxcell Mega Shield. I've only tried the UTFT and URTouch libraries from http://www.rinkydinkelectronics.com/ Their example sketches will run but only for a limited time then I get the blank white screen. Each time they run it is for a different period of time, but never more than a minute. With the shield and the touch both installed, the board will run the basic Blink example for what seems to be an infinite time. I think this is a hardware problem since the example sketches work for a period of time, and also because how long they work is random. Any advice is appreciated.