Late 2008 MacBook Pro turns off when i plug in its charger

Hello! I have a Late 2008 MacBook Pro that I use fairly often as a second computer. I have been using it daily for the last week and everything has worked fine, when plugged in and when unplugged. My problem occurred last night when I plugged the charger into the charging port. The laptop immediately shut off. It took me a few minutes to figure out what was going on, and it is that the laptop will run fine when unplugged but will shut down as soon as I plug it in.

I want to know if there is any way to fix this issue, or if I should just get a new charger. Or if it’s even the chargers fault.

One thing I have noticed is that the charger lights up green and yellow when not plugged in, which is something I have never seen. When it’s plugged in it just blinks green.

Thank you!