Acer aspire 4920 charging mechanism failed

Question

i have an acer aspire 4920g and charging mechanism does not charge my battery so therefore i can not use it running on batery i wish to know how i can fix the problem and how much would it cost me to see whether i should buy a new laptop. first i thought its was a battery problem so i bought brand new battery but it does not charging the new battery and then i realise that the charging mechanism of my laptop failed coz the charging light do not turn on when i plug in the adaptor . thanking you for answer my posted problem. i also replace a brand new charger and currently running my laptop with it but its still doesnt charge my battery. my conclusion is that charging mechanism in the main board is gone and if u know a way to fix that part without replacing a main board or the name for that part so i can buy it and fix it myself. my next move would be open it up and testing the power supply do have a fault and can i just replace the power supply instead of the main board?