ST2410, black screen with very faint image

With HDMI connected to PC, a very very faint Windows background image can be seen.
I unplugged everything and pressed monitor ON button for 5 seconds
Then I plugged in the power cord only.

When I press Button 1 + 4 I am supposed to get a grey screen. I don't it is still black

When I turn the monitor on I am supposed to get the floating dialog box against a black background constantly floating all over the screen. What I get is the dialog box pops up for 1 second and it is very very faint. It disappears,

Should I just toss the screen in the garbage?
I cant use the menu because it pops up on the screen very faintly for less than a second and then disappears.