Try connecting it to an external monitor and hitting the key combo to turn on the external display (usually F7 or Fn-F7 on a Thinkpad). If that generates no picture (or rather, a white picture like your screen), then the video card on the laptop is probably dead. The only way to fix it would be by swapping the CPU (video is built into the CPU on that model), which may not be possible since they're usually soldered in.
If it does generate a picture and the laptop is usable connected to the external monitor, then probably the internal connector to the LCD panel broke or popped off, or the electronics driving the panel died. If you're mechanically inclined, you can take apart the laptop to check the connector (along the bottom of the...