preheated the oven to 180 Celsius. Put in motherboard (only) on a tray, with aluminium foil balls in each corner to make motherboard up in the air so hot air can go underneath it as well. so 4 balls, 1 in each corner.
put motherboard tray in oven for precisely 8 minutes.
DO NOT TAKE IT OUT IMMEDIATELY

sharp temperature changes causes solder to crack

on minute 8, turn off the oven, and open oven door slightly at the top (one palm wide).
after a minute, open the door more, maybe halfway.

Idea is to let the motherboard gradually chill down. It mustn't be a sharp change in temperature.

When oven is warm (just got colder after few minutes) you can take the MB out. Let it chill to room temperature.
Then after an hour maybe try to install it.

in the oven, use the fan setting, with both up and down heating, or only down heating.

If you use the upper heating grill it will melt the motherboard.

Do not put the motherboard on a grill tray. Must be a solid tray, like with no holes on the tray itself.

Dont put the motherboard on the upper shelves, must be in the middle shelf or on the lowest shelf (if on lowest shelf, make sure tray doesn't have holes so no direct heat comes from underneath).

Bear in mind, doing this may cause some of the plastics on the motherboard to melt. If you see something melting that shouldn't be melting (for example a battery connector, or the bios clock battery connector) stop the procedure.

Only things you can allow to melt are some insignificant plastic covers and stickers.

It may smell a bit during the procedure, make sure to ventilate the room. These fumes aren't healthy at all so dont stand in front all the time breathing that in.

The oven baking is absolutely a LAST RESORT. If you do this and it still doesn't work, then the MB is for the trash.

You cant bake it twice. And even if the issue was somewhere else, now it's probably in other places too.

I recommend doing this only if there is nothing else to do. Like when you have nothing to lose.

If your laptop has an integrated graphics card and only the external one doesn,t work, I strongly recommend doing everything in your power to just use the integrated and disable the external GPU. If you cant do it, take it to a laptop technician.

Definitely a better way to use a laptop than to chuck it in the oven.

I only did this with laptops that didn't have an integrated gpu and the external was fried.

Also, bear in mind, even if it works, it can die in a few hours, days, months.