Laptop wont turn on without battery in - Acer Aspire 5920-6727 Notebook

Take out the battery then press and hold power button for about 30 seconds, then put battery back in again and try to turn on. Might as well leave it without the battery for some time after holding the power button. If that doesn't help try removing RAM and turning it on without it.
By the way.. any beeps?

problem with the battery, try another battery. this will fix it.

Remove the Battery and press power on for 1-2 minutes with out AC power .
Please turn on the laptop with only AC POWER (without battery ). Check it. it may turn on your laptop.

If display ok, then insert battery and use it...

Did you try just on battery power alone? Also try powering it up on AC
and the battery removed. When it turns on for a second, do you hear any
beeps?

99.9% of most laptops can run without
a battery.

try to remove the battery. Then connect the power cord (Adapter) to your laptop and plug it to the wall outlet. Now turn ON your laptop. It should boot well without the battery and you can conclude that the battery caused the problem. You can then replace the battery.

Yes, remove the battery from the laptop.

Plug-in power adapter and turn ON laptop (without battery).

After the laptop starts up and Windows has settled, put battery back in the laptop.

Allow to charge for a few hours.

Verify that you obtained an exact replacement power adapter for the Dell. If it is an exact replacement then try this. Disconnect power adapter. Remove battery. Reconnect power adapter without the battery. If it turns on, then power off and place battery back in. Then try again. If problem returns, there could be a problem with the battery itself.

This normally means your battery has failed. Have you tried booting the laptop with the battery removed? It should boot fine without the battery and if so you will need to contact Dell about getting a replacement battery.

I assume that by now the battery has discharged past the point of being a useless diagnostic tool. Either the charger failed or the laptop failed. Have a reputable repair person put in a freshly charged battery to see it the machine will run off battery only. If not leave the whole unit with him/her for repair.

Try to remove the AC power and then the battery. then plug in the power without the battery. Turn-on the Laptop if it starts then slowly put the battery back after it boots in windows. Check if the battery is charging.

Hope this helps.