Battery or charger, please help!!

Hi I have an old macbook '06. When I plug in the charger it was not going
Green but remaining red, i took out battery and tried again now theres
No light at all and the computer wont turn on

Is this a battery replacement or a charger replacement?
Thanks

With a machine that old it could be either. If you can borrow another charger from someone and see if that works, it would help to eliminate which is bad.

A new battery is going to be around $100 or more whereas the charger should be around $45 - $50.

Did you try to recalibrate you battery ?
See this : Intel-based Macs: Resetting the System Management Controller (SMC)