DS Lite problems - need diagnosis.

Screens are white. Bottom screen is white with color bands on the left side. Top screen is just white. Touch recognition of bottom screen seems to be working.
DS can sometimes reach the DS startup screen, other times the power will be on but both screens will be black.
Sound works fine.
Can load DS games, but freezes after about a minute of play.
Pressing on the bottom screen can cause the top screen to display properly, but only temporarily.
After freezing and turning off the DS, pressing on the bottom of the screen allows it to reach the startup screen again.

I'm guessing it's a problem with the motherboard, but I want to know for sure.