Will the laptop still boot up using it's battery? Please do try these test that may help in identifying the issue.
- Start by testing the AC adapter if it's still working properly.
- Remove the battery off the laptop then try powering it on with just the charger connected and see if it will boot up.
- If the laptop will not boot up with just the AC adapter connected, that could mean that it needs a replacement already.
- But if the laptop will still boot up with just the AC adapter connected that means it's still working. While the laptop is on, insert the battery back in and see if the same problem will persist or not.
- Do also try a different AC adapter that has the same voltage and see if that will work or not.
- If all these will not work, do replace the AC adapter already since it's already faulty.