black screen coming on my hp pavilion DV4 2123tu

[appy21]

What To do if black screenis coming on the starting of laptop and there is a blinking of undercore sign (_) on left side of screen? PLz TeLL me ...

 

[drifter77]

Try rebooting your computer and keep pressing F8 until the boot menu shows up. From there, choose "Last Known Good Configuration" and see if that works.