It seems like a problem with your battery already but please do try running these test.
- First, do test the AC adapter if it's still working properly.
- Remove the battery off the laptop then plug in just the AC adapter and see if it will boot up normally.
- If the laptop will boot up normally without it's battery that means the AC adapter is working properly.
- But if the laptop will still not boot up that could only meant that the problem is the AC adapter.
- Do also try a different AC adapter that has the same voltage and see if it will boot up.
- Again if the laptop will boot up with just the AC adapter then the problem is the battery and replacing it would be the only solution.