Need assistance to replace a damaged screen

Hi everyone

I bought about 6 months ago a Dell Precision M20. I liked so much its FireGL 3100 graphics that I couldn't resist to buy a Dell Precision M70 when the occasion came by. The graphics on the M70 is a Quadro FX1400. I got the M70 for a good price as it has a damaged screen. My plan when I bought it, was to fix it and sell the M20 to get my money back. The fault on the M70 screen is the appearance of white vertical lines on the middle of the display.
The original screen is a wide mate 15.4" screen made by LG/Philips (resolution: 1920x1200). The reference of the screen is LP154WU1. The replacement screen I used for the repair is glossy and is from AU Optronics (resolution: 1280x800). The reference of the new screen is B154EW01.
As you can see from the pictures below, at the boot and up to the appearance of Windows desktop on the screen, the display is split into 4 parts. When the desktop is on the split disappears.
1- Can I use this laptop with the new screen without risking damaging the laptop or the screen?
2- I can't seem to be able to change the brightness on the new screen. Any suggestions on how to fix this problem?
3- Would a bios update fix the brightness and the display problem?
4- The laptop runs a bit hot due to the dedicated graphics. Once the screen problem is fixed, I'm planning to put some Artic Silver 5 on both the CPU and the GPU. Then to undervolt the CPU. Can I also undervolt the GPU? If the answer is yes, please advice on how to proceed.
5- When I use the Dell charger everything works fine. When I use a universal charger the laptop works fine but the battery does not charge. Is something wrong with the universal charger?

Thanks.

 

please help