Dead motherboard? I need help

[TheSinfulOtaku]

A problem with my second pc/ HTPC made from my old components, the specs of which are on my profile because this is an old account.

 

The motherboard is a Maximus V Gene, its been working fine for the past uhh 7 years?

 

Suddenly about a month ago it started acting weird, the CPU fans HDDs and case lighting would turn on even when the motherboard/pc was turned off, the pc would still boot as normal and everything worked fine so I am unsure why it was doing this, I use it once a week maybe, and it wasn't doing this before.

 

and now its started not booting at all, I was getting an error code of IU or something along those lines after changing the graphics card, I took the card out and tried to boot it again and this time no codes at all the code display is completely blank, the PC doesn't turn on at all as if I haven't even pressed the power button, however the CPU fans are still spinning like they were before with the power going through the power supply and the case lighting is on.

 

Could it be a short? I can't figure out if my board is dead, should I take the board out of the case and look for damage?

 

I really can't figure this out, the CPU cooler is a tower type Akasa cooler, and the case lighting is Bitfenix alchemy RGB. 

 

Anyone have any ideas what to try? 

 

EDIT: the power supply is a Corsair VS650 I got off ebay because I had given my old power supply to my brother, and the graphics card I was putting in it was an MSI R9 390 

 

EDIT 2: I have tried unplugging everything apart from the motherboard cpu power and cpu fans, and it still does the same thing, could it be power supply because the HDDs are not even connected to the motherboard but still spinning up, and the motherboard lighting still comes on around the Audio chip.