My sansa e250 mp3 player just fell down, after that, when i restarted it it is just showing the blue light but not showing the display on the screen. Any help would be appreciated.

Drop it again from a similar height

OK this is going to be hard to believe....the exact thing happened to mine. It dropped about half a meter onto a concrete floor and showed up with a blue screen and wouldnt shut off.
I unscrewed the back panel and unplugged the battery hoping that it would reset. After several restarts and unplugged batteries it was still unresponsive with the blue screen of death. So like any good tech i tried to reproduce the sequence causing the failure. I dropped it onto my work bench and plugged the battery back in. Worked perfectly after that and has continued to work perfectly since (nearly a year later).
I made sure i covered it with one of those cheap silicone covers after to hopefully absorb some shock after i got it working again. After a year of brutal treatment on military exercises this is the one and only problem i've ever had with my sansa.
Good Luck