Dell d630 Video intermittent problems. LCD Screen shows lines. CRT mode screen shows res. out of range

Hello, 

I want to first apologize for long posts. I have been working on this problem for weeks and felt i needed to bring you up to speed on what steps I have taken already. I am no expert, but I have years of experience with PC's and i'm sorta new to laptops. Thank you for understanding :emotion-1: If I have left out any info that is needed, please ask.

I have a Dell Latitude D630. I've had it for a year or so. Got it free. it had been dropped on the corner. I rebuilt it. no damage to Lcd, it was missing a cd drive and needed a new bottom shell. It has worked great since.

Until... one day i used it in the morning and then that after noon, I turn it on and .... no video. just lines in the LCD. now I assumed the LCD had been damaged but i could not play with the connections to get it to change or flicker even. i connect a external monitor and It gives me an out of range res message. i turn it off and boot it back up and the external monitor would show fine until the vista boot screen. It show a few blue dashed vertical lines. then if i switch to the LCD again sometimes it work other times it doesn't. I had it sitting for about a week or 2 and turn in on and without problems it ran fine, however the screen did eventually go to lines again. (always a different pattern, not following a bad LCD lines which have always had the same pattern in my experience anyway)

Now.... my conclusion is that the video on the board is bad.

First, Can one of you give your Diagnosis? 

Secondly, Finding a new MB for my Dell has been very confusing. I think I have found that there are 3 different MB out there. DX686, DT781, and R872J. one has nvidia GPU, the others have Intel GPU. My heat sink has 2 different legs going out from the processor. which I think tells me that I Intel graphics ( Nvidia has Three?)

And Finally, is there an upgraded MB that I can drop in that maybe is running a faster CPU? or is more reliable? (mine says its a Centrino Duo on the arm rest, the CPU Chip has T7100, 1.80/2M/800) 

Thanks for all your help, 

Dustin