Inspiron 7779 Wont turn on, power light on, fans spins then stops

[AuntDae]

Please help! My not so old Dell Inspiron 7779 Laptop will not turn on. I was trying to set up a StarTech DisplayLink dock and everything was working fine until I plugged in the HDMI cable into the port on the laptop. My laptop suddenly turned off and will not turn back on. The power indicator light it on, the fan tries to spin then quits. I've tried disconnecting the battery and isolating each component adn even tried another PSU but nothing is working. Could it have fried the Grahics Gard? I really don't want to purvchase a new MOBO. Any help is greatly appreciated!