Laptop turns on but no display(Acer Aspire 3 A315-57G)

Sorry for this big post. But I'm in serious trouble. Please read carefully!

I wanted to disable the dedicated MX330 GPU from BIOS. Thus I got to BIOS by holding FN+TAB keys then pressing F2. There appered an extra Advanced tab with the regular Advanced tab. By default Acer Laptop's BIOS doesn't offer that much settings.

I changed the GPU to iGFX. Also I changed the ram frequency to 3200mhz which was set to 2666 previously. After doing these two changes I saved them and restart the laptop and then the problem comes up. it doesn't display anything, even no light on display. Only the two blue lights of charging and power on. The fan also spins normally.

I tried CMOS reset by pin hole that didn't work. Then I opened the back part and reassembled battery, SSD, and the CMOS battery. And every other possible ways I can find on the internet. But nothing worked for me.

I don't have extra monitor to try 2nd display output. I tried with keyboard, the NUM Lock or Caps Lock light don't turn on.

I desperately need this laptop in normal condition. Please help me.

PeterOz said:

What is the SNID number
it will be on a sticker

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11001862776

PeterOz said:

when you reset cmos battery leave out for 10mins
Have the power cord and the main battery both disconnected.

Click to expand...

Do I have to disconnect the cmos battery also?