Need some help !

[Rumble39]

Recently, I had a huge problem. I was gaming on WoW with some friends and in the middle of an instance, my computer crashed and was unable to boot windows. I had a problem similar a few month ago and it was my old HDD. So this time I was thinking my 4 years old SSD was the problem, but no it wasn't. I took my graphics card out and tried to boot the computer using the CPU Graphic card (I have an i7 4770k) and boom work like a charm (Oh yeah I changed my old SSD and reinstalled Windows). Now i'm thinking if it's my GTX 780 Ti the problem or something else. Without other computer to test my GC I bought a new PSU (EVGA Supernova 750G2) but when I plug everything on the new PSU my pump won't start and I get the code '99' on my motherboard. Now i'm confuse why my pump for my cpu won't start with the new PSU but work on the old one.

 

Little recap : I don't know why my Graphics Card doesn't work anymore and don't know if my PSU or Motherborad can be the problem. I need your help !!!

 

Parts: ROG Maximus Formula VII(Mobo), i74770k, Corsair HX 750(Old PSU), EVGA Supernova 750G2(New PSU).

 

P.S Sorry for the poor english, it's not my first language.

[sethy55]

Is it not booting and if so is it moduler 

[Rumble39]

When I start my computer with my old PSU (semi modular I think) and the 780 Ti I can't pass the little blue windows flag without the screen turn off and doesn't detect any output. When I take the GC out and plug my screen on the mobo it work just fine.

[Rumble39]

after seeing the blue flag for a couple of second, my screen doesn't detect any output from the GC. 

[sethy55]

Have you tried switching the pcie lane it's in

 

[sethy55]

And if you have any other cables for the pci power try switching it

[Rumble39]

Picture of both PSU

[sethy55]

What where you doing when it stopped 

[Rumble39]

Nothing Windows couldn't load at all with the GC plug in. it work just fine when I take the GC out

[sethy55]

Do you have a spare gpu

[Rumble39]

oh when my computer crashed I was playing WoW after that I couldn't start it without taking the GPU out. My friend lend me his old GPU ( radeon HD 6990) but I was lagging pretty hard. I tested Player Unknown Battleground and World of Warcraft. PUBG was lagging really  hard and wow was playable but not the best compare to my 780 Ti.

[sethy55]

Have you oc it

[Rumble39]

nope

[sethy55]

If you don't have  any more  warranty  than you could look at the components 

Or switch pc and test it

[Rumble39]

So you think the problem is the GPU not the PSU or motherboard ?