After replacing thermal paste on my two GTX 980ti, no display signal and B2 error VGA light on mobo

[murac_sm]

Hi guys, I'm asking for some advice on my two GTX 980ti G1 gaming from gigabyte. I decided to replace thermal paste on them since they were getting pretty hot as of late. After I did this, and I put the GPUs back in my case to boot, I would get no signal from my monitor, and the mobo would signal a b2 code with a VGA light on. The GPUs fans are spinning, but I'm getting no signal from them. I tried many thing after that: I tried with only of the two (tried both of them) in different PCI slots but with no luck, then I tried reseating ram and resetting CMOS, but to no avail. I tried booting with mobo integrated graphics and it works, so I'm starting to believe something bad happened to my GPUs. Is there something else I could try to do? I intended to change them in a few months, so I'd like to understand If I can still do something about it or I should speed up the purchase. Thanks in advance.

Here are my PC specs:
CPU:i7-8770k
GPU:2x Gigabyte 980ti G1 Gaming
RAM: Gskillz Trident RGB 2x8gb
MOBO: Asus maximus X Hero wi-fi AC
PSU: Corsair rm1000i
CASE: Fractal Design Define R5

 

[Lutfij]

Make sure you're on the latest BIOS update for your motherboard. Then look to see if you can work with the GPU placed on the second PCI-E x16 slot for both cards. See if removing the CMOS battery and replacing it after 15 minutes changes your experience.

 

[Rdslw]

Make sure you're on the latest BIOS update for your motherboard. Then look to see if you can work with the GPU placed on the second PCI-E x16 slot for both cards. See if removing the CMOS battery and replacing it after 15 minutes changes your experience.

in my experience battery helped.
remove the power
remove the battery
remove the card,
grab lunch,
connect them back in reverse order, go to bios and restore defaults.

 

[murac_sm]

Make sure you're on the latest BIOS update for your motherboard. Then look to see if you can work with the GPU placed on the second PCI-E x16 slot for both cards. See if removing the CMOS battery and replacing it after 15 minutes changes your experience.

in my experience battery helped.
remove the power
remove the battery
remove the card,
grab lunch,
connect them back in reverse order, go to bios and restore defaults.

I tried as both of you guys suggested, updating the bios and replacing the cmos battery, but I keep getting the same error. Is there anything else I can try?