Weird problem with Latitude D800 - won't boot with hdd, boots w/o

I have strange problem with my Latitude D800.
It won't boot and shows only lines across the black screen or blurs when HDD is plugged in.
When i remove HDD (any HDD, i've tried three so far), laptop boots to BIOS.
Seems like mobo problem?

 

Huh, I've never heard of such a problem before... did it suddenly start happening out of the blue? Have you tested the aforementioned three hard drives in other machines? How big are they? Can you take a picture of the lines? I'd like to say it isn't a motherboard issue since you can get into BIOS with an HDD... but with weird issues like this, it's really hard to tell.

 

I've got this laptop from somebody else, they said it just happened.
I tested HDDs on other machines, they are good. one is 30gb, another 40, and another is 80gb.
When i turn it on with HDD plugged in i can get one of these:
1. screen is black
2. short thin horizontal lines across the black screen
3. big white-gray blur which fills entire screen.

Could it be some video card problem?

 

Can you boot off a Linux Live CD? That would show whether the basic hardware is OK.

John