Unplug all cables from the monitor (at the monitor) except for the power cord. Turn on the power and allow the self-test to proceed. Check for bent pins on both ends of the data cable. Reconnect the monitor cables and be sure to re-check that the thumb screws are tight. You should not see a self-test if the cables are connected, undamaged, and the video card is OK!
Follow the users manual and press the correct buttons, in the correct order the brighten the screen even though you can't see what you are doing. I think on that model, you just press and release the right arrow, then press and hold it to brighten the screen.. But again, this won't be available during the self-test because there is no signal. If it says "Cannot display this video mode," then the PC settings are wrong.
Let us know what you find out. Following is a link for the users manual:
http://support.dell.com/support/edocs/monitors/E151FPB/En/controls.htm
Good Luck
