My Dell XPS Battery Died

You asked the same question yesterday, and the answer is the same:

Unplug the battery from the system board and plug in the AC adapter.  If the system won't power up on AC alone, the issue is not the battery.  It's more likely the system board that's bad.

If you need further help, you'll need to supply the model number. There are three different XPS 12 models:  the 9Q23, the 9Q33 and the 9250.

I realize I asked the same question. I also only got back a message asking for my Service Tag, then I was told my warranty expired, and someone in the community would have to help me. That was the last message. I did not see any type of response on what to do to try an solve the issue. I appreciate your answer.

See the above reply.

Disconnect the battery from the system board.

Plug in the AC adapter.

If the system will power up, you simply need a new battery (the system will run on AC power just fine in the meantime, and since you asked about backing up data on the drive, you can now do that).

If the system won't power up on AC only, it's likely the mainboard is bad.  Since this will be several hundred dollars' worth of repair, given that the system is a minimum of several years old, it may make little economic sense.  If so, you can still read the drive if you remove it from the system and purchase an adapter to connect the it to a working system.  If you need a part reference, answer what I asked above:  what model?  9Q23, 9Q33 or 9250 and someone can recommend the required adapter.

If you cannot or will not attempt the above, any competent computer shop can also do the job, though expect a substantial labor charge if they recover your files for you.