[Yung Lean]

Hello SL

Need help with this issue before you say anything ( I DID LOTS OF GOOGLING about the problem and none solutions helped to fix mine )
Ok going to tell all story from beginning
I have this Acer laptop which is great never had problems with it until now
Couple months ago it started to do this weird thing when I plug power cord in laptop just shuts off then starts again then when it starts booting Windows/Linux it shuts off again and starts again and does that over and over again.
So I tried to turn laptop on without using power cord and guess what it perfectly boots up and works until battery dies. But doesn't work with Power Cord. I tried to turn on laptop without power cord and then plug it in when its fully boot up but it instantly shuts off and starts doing same thing.
Then I tried to google for the answer and the possible solutions I found was
Bad power cord ( So I changed it to new one but it still did the same )
Dead motherboard ( But if motherboard was dead it wont even boot up or allow me to enter Bios )
Battery dead ( but battery can't be dead if I leave laptop off with power cord in it charges up so when I remove it I can use the laptop *also battery holds like for several hours so can't say it's that bad* )
Then some other solutions like taking out battery for 10 seconds then putting it in while holding power button and so on and none of that work.
So I ran out of ideas what could this be so came here to ask you guys maybe some of you have encountered this problem and found a fix for this.