Here’s a solution that works for me:
Whenever I turn on my Sansa I get white screen. I even stopped using player for several months and then when I tried to open player’s case just for fun it started working normally. Now, when I turn on player I get white screen, so I open slightly player’s case from bottom and it works. Worth noting is that I didn’t broke anything or modifided player.
So if you lost any hope, try this solution. Anyway you have nothing to lose. 
