Sony VGN-T150 - Manual (Page 183)

Why did the computer screen (LCD) go blank?
 Your computer screen may go blank if the computer has lost power or has entered a power saving mode (Standby
or Hibernate). If the computer is in LCD (Video) Standby mode, press any key to activate the computer screen. See
Using power saving modes for more information.
 Make sure the computer is plugged into a power source and is on. The power indicator on the computer will be on if
the computer is on.
 If your computer is using battery power, make sure the battery is inserted properly and is charged. See Using the
Battery for more information.
 If the display mode is set to external display, use the Fn+F7 key combination. See Selecting a display for more
information.
Page 183