Hi ANDREWHELP,

The system should be able to power on with the adapter connected, regardless of the battery's presence.

When you press the power button, do any leds come on? What is the issue with the battery? When was the battery working fine last? Are you able to test this battery on another machine or another good known battery on this machine?

Are you using an original Dell OEM Adapter? When you plug in the adapter to the system, does the adapter stay firm or does it fall off easily? Is the adapter frayed? Is there any damage on the system? Could you test with another power adapter if possible?

Does the adapter led stay on and stable or does it go off when connected to the system?

Please check if there is any damage on the machine. Check if all the ports on the machine are fine or misaligned. Sometimes if the pins in the USB ports are touching each other, they are known to cause many issues on the machine.

If another adapter works fine, then replace the adapter. If the adapters are loosely fit and sometimes it powers on with another battery, then replace the dc port - http://bit.ly/2egjkJy. Otherwise, the motherboard needs to be replaced.

If the system is under warranty, Please click my DELL-username and write me a private conversation with the service tag and your contact details(Name, Phone#, Address and Email). If there is no warranty, then you could contact our team to get a quote for a paid service call - http://dell.to/1vnT6CQ

Let us know if you have any other queries.