How to fix dell Inspiron 5040 laptop windows 7?

Remove the battery from the laptop, connect the charger and turn in on.
If it don't turn on, then there are 2 possibilities:
1) The charget is blown and need to be replaced. (bad)
2) The laptop itself is fried. (Very bad)

Now, unplug the charger and put back one of the batteries.
Turn the laptop on.
If it don't come on, try the other battery.
If the laptop fails to turn on with BOTH batteryes AND the charger, it's dead.

It's hard drive is possibly intact. Remove it from the laptop and try connecting it to another computer to test it.
If the drive works with another computer, all your data are safe. Otherwise, I can only hope that you have a decent and current backup.

Electro
January 2015