Nothing displays on monitor screen

[NiceSeeingYou]

I have a Toshiba Satellite L305D-S5881,
with a AMD Turion, X2 Dual-Core Processor RM-70, 2.0GHz, 3 Gigs Ram.
A customer gave it to me because nothing shows on the screen.
The customer replaced the laptop battery and replaced the plug-in,
thinking this would fix the problem, but it did not!
So I removed her hard drive to destroy, and 1 by 1 I did the following list of things.
Computer does turn on.
I installed a "New 500 Gig Hard Drive" and tried to install Windows 7 - 64 bit,
but nothing shows up on screen.
I disconnect the power adapter from laptop, removed the main battery from laptop, held the power button down & counted to 20. Re-install the main battery, reconnect power adapter to laptop & turn on laptop, still black screen.
So after much research on line I replaced the soldered on "motherboard battery"
with a new one, but this did not resolve my problem.
So I did further research and decided to replace the "monitor screen" with a new one,
but this did not resolve my problem.
So I did further research and decided to replace the monitor "Inverter" with a new one,
but this did not resolve my problem.
I have switched the ram, then tried to boot, but this did not resolve my problem.
Then I replaced the ram, then tried to boot, but this did not resolve my problem.
I removed the battery, then tried to boot, but this did not resolve my problem.
I can not access BIOS, nothing shows on the screen even if I hold a flashlight to it.
I hooked up an external monitor, then tried to boot, but nothing shows on that monitor either.
I just got done heating up the graphics cards, but this did nothing to resolve my problem.
Anymore suggestions would be appreciated.
Thanks in advance!
Keith

P.S. Update:
I read somewhere on line to try this:
I took a Hair Dryer and for 5 minutes, I heated up the graphics card in a figure 8.
I then put it all back together again, and turned it on and guess what?
I could see something on the screen for the first time ever!
It went into the BIOS, I was able move around in there, but I wasn’t able to change any settings.
So I rebooted the computer and now I am back to a black screen again!
I don’t understand why it turned on for a moment but not again?
And I don’t understand what the heat did to it?
Anyone know?
Thanks
Keith

P.S.S. Update
I have given up on fixing this laptop, so I dissected it and am selling off the parts.
I appreciate the opportunity you gave me by allowing me to post in your blog.
Have a great day or night whichever it is.
Keith

 

[ffg7]

try this if you haven't already. disconnect power adapter from laptop. remove main battery from laptop. hold the power button down & count to 20. re-install main battery. reconnect power adapter to laptop & turn on laptop.

 

[NiceSeeingYou]

I tried that but forgot to tell you, sorry.

 

[NiceSeeingYou]

try this if you haven't already. disconnect power adapter from laptop. remove main battery from laptop. hold the power button down & count to 20. re-install main battery. reconnect power adapter to laptop & turn on laptop.

I tried that, see my latest update in my message, do you have any idea on why it worked briefly? I am about to give up on it.
I appreciate your time.
Keith