Graphics card not posting to monitor

[rockalfk]

So i have had a custom built computer with a 1070 for about a year now and a few days ago i decided to throw in an old 760 into the mix just to see if it would work. after doing this the graphics cards will not post in any pcie slot. and when accessing it through the onboard display windows 10 does not detect any graphics cards.
I have tried:
Cmos reset
trying each card individually in different slots
----the only time it posts is when it is plugged into onboard graphics
uninstalled all display drivers
bios made PEG priority
furthermore my computers components are
mobo: z97 gaming 5
graphics card: 1070 ftw/ 760 sc
psu: corsair 750m
hdd: 2tb
sdd: 250gb 850 evo
update: is it possible for all 3 pcie to break at the same time because when plugging the graphics card into a seperate computer it posts just fine

 

[acer2dn]

Probably not compatible. Or the card died.
Is it pushed into the pcie slot all the way? Sometimes if its wiggling out a bit it might not show display

 

[rockalfk]

Probably not compatible. Or the card died.
Is it pushed into the pcie slot all the way? Sometimes if its wiggling out a bit it might not show display

i have fully pushed it into 3 different slots with no success

 

[hang-the-9]

Try resetting the motherboard, unplug from wall power, remove CMOS battery, hold in power button for about 30 seconds, try the card again.

 

[rockalfk]

Try resetting the motherboard, unplug from wall power, remove CMOS battery, hold in power button for about 30 seconds, try the card again.

still wont post

 

[rockalfk]

I gave up and sent the mobo back via rma