My Toshiba Laptop Just 'black Screened'. No Display On An External Monitor Eithe

See page 77 of your manual

http://www.manualowl.com/m/Toshiba/Satellite-L505D/Manual/281191?search=fn+keys&x=87&y=22

 But there are several other possibilities. 1/ This method sometimes works ---  Turn off your computer  Disconnect  everything from it including power lead  Remove the battery from the LAPTOP. PRESS AND HOLD POWER BUTTON FOR 30 SECONDS, OR, SO.  Re-plug in the power supply. (leave the battery out of the computer) Press the power button  The screen will often work.(strange, but true) If it does, Choose start windows normally. If the scren now works...... Sometimes Hibernation can get stuck-if you get the screen back- turn off hibernation, and I usually set the screen to nver turn off.   Power settings has been known to play up, --Go to Control Panel - Power Options - If it's on 'balanced' - click change plan settings Then   Change advanced power settings  See  Processor power management and change the minimum processor state from 5% to 100%  Click Apply then click OK Then shut down, unplug power cord, and replace battery, replace power cord, and restart.  2/ Try putting pressure to the rifgt of the mouse pad, with a heavy palm of your hand , and see if anything shows- if so,the solder to graphics chip is usually the cause.(this seems to have happened with Invidia chips mostly)