Dell Inspiron 24 7459 shuts down

It is best to press and hold down the power button for 30 seconds or so to shut off a frozen computer, NOT pull the plug. Pulling the plug can cause damage.  Also make sure you have not updated drivers or bios yourself. All in ones are more like laptops and do not need driver or bios updates unless Dell notifies you of updates for your exact model. All updates must come from Dell not Intel or other manufacturers.

Did you try a reset of windows? Settings, Update & Security, Recovery. The hardware is still under warranty but the software is not.

I purchased mine April 2016 and have the exact same problem.  Did your computer come with the Intel HD Graphics 530 and the GeForce 940M?  Mine has never generated a Dump File or Blue Screen, it just turns off.

You seem confident that its not the heat but i willl start with heat  anyway, check if

1. The computer fan is working properly
2. Run the Dell ePSA tool and check if an of the various parts are operating properly
3. Ventilation, anything covering ventilation.
4. Hardware, if you installed any additional accessories

You can also try the what i call the bush tactics found on this inspiron laptop article

Software

1. Driver problems may happen if you installed third party apps to control/enhance functionality of your computer
2. Malware, viruses and so on
3. Windows updates also fixes hardware compatibility problems.

If the Dell ePSA tool shows errors then go on from there.