Display or LCD Panel problem with Vostro 3450, please help.

I volunteered to help with my church's music director's laptop, which is a Vostro 3450.

When presented to me, the laptop would not boot up fully.  On startup, I would get an 8-beep error code and there was nothing on the display.  I hook up an external monitor via vga port. Shutting the laptop lid would transfer the video signal to the external monitor, which displayed the dell bootup splash screen, but there was no progress to bootup and the laptop was unresponsive.  Also, the 8-beep error code continued to sound annoyingly and endlessly.

I reseating the LCD panel cable connector and the symptom stayed the same.  I looked for signs of dropping or abuse and found none.  I ordered a replacment LCD panel and installed it.  I did not come across any difficultly in replacing the screen and nothing seemed out of the ordinary.

After replacing the LCD panel based on the part number on the original panel, the laptop will now boot up fully and is completely functional via VGA connected monitor... but the LCD panel is still giving me a problem.  The backlight seems to  be on, but the screen seems to be gray/black and has no response.  sometimes there are thick, uneven vertical bars on the screen which are a lighter shade of gray.  There are no error codes associated with this new symptom.  After looking into a few things, I reinstalled the original LCD panel and the original symptom returns.

I contacted the seller of the panel.  They sent me another new panel, and the symptom stays the same.  Laptop boots up fully, but the screen is gray. 

One interesting thing is that if I switch the display to show via VGA and AND the LCD panel, the lcd panel still has a dead grayish screen, but now it seems to be dots, almost like it's displayed in poor resolution.  Also, the external monitor has poor image quality, but I'm attributing that to the 4:3 monitor getting a wide-screen signal.

I can't seem to find which diagnostic path to go down.  Do I blame it on the motherboard? Do I take the laptop further apart and look for cable damage? Do I just give up and advise the church they need to invest in a replacement?

I'd hugely appreciate any ideas or suggestions on what my next steps for discovery should be,

Thank you