I have some hardware experience and never seen this.
My problem is that I have a computer that sometimes, after i press Power On, starts the fans and after 3-4 seconds shuts everything down... The fans stop working but the front light keeps turned on.
I have tried the following things:
1- inserted some cooling processor fluid.
2- changed graphic card
What makes me loose my sleep is that this only happens sometimes!! Other times everything works and I can use it.
Nothing is displayed on the monitor when computer doesn't boot.