Fix Dell Inspiron 5400 AIO Boot Failure with White Power Light

Guys, I have an Inspiron 5400 AIO at Tribeca Dental Associates - Greene. They are trying to turn it on, but nothing happens, just a white light on the power button,no BIOS screen,nothing. I followed this,tried to hold the smaller button, nothing happened either : https://www.dell.com/support/manuals/en-us/inspiron-24-5400-aio/inspiron-5400-aio-setup-and-specifications/bottom?guid=guid-0a15b9bb-9b51-479e-be50-aab2a43507ef&lang=en-us How do we proceed in this case? The computer has been bought 3 years ago, I see that they have Dell Pro Support, but not really sure how it works.

if it happens to be under warranty still by chance you can just call dell and have them check it, and they can probably go onsite to replace whatever is broken on it o.o