PC won't POST after installing GTX970

[Quinnens]

Hi, i build my new pc two weeks ago, and it worked fine, until today my new GeForce GTX 970 arrived and I installed it. The fans spin up, and stop again instantly, no POST.

The only thing I changed was building in the Graphics Card. It's an ASUS Strix GTX 970 OC-Edition.

I then tried to boot without the 970 again, but now there is the same problem: no post at all. The fans spin up, stop, that's all.
The Graphics Card has a power-led to indicate if it's powered, which is lit, so it's probably not the PSU.

My Parts:

• 
  ■Intel Core i5-6600K
  ■Gigabyte B150M-G3H Mobo
  ■Corsair Vengeance LPX RAM (2x 8GB)
  ■ASUS STRIX GTX970-DC2OC-4GD5 Graphics Card
  ■Thermaltake Berlin 630W
  ■Intenso 512GB SSD for Win10 + WD Blue 1TB 7200RPM
  ■Windows 10 Pro

I already tried these steps:

• 
  ■This troubleshooting
  ■Clearing CMOS
  ■Only CPU and RAM
  ■Checking for any shorts, didn't find anything
  ■Removing RESET-Plug

I would really appreciate if somebody could help me here, my old notebook is slowly giving up...

Cheers,
Quinnens

 

[tsnor]

Make sure (again) both MB power plugs (the 4/8 and the 24) are firmly installed.

Can you blow out the x16 PCIe slot you used to make sure you didn't push dust down into the slot shorting it. Use a can of compressed air.

Since you've done the debugging suggested in the 'no boot' sticky then you've tried this system with just the MB, PSU and CPU+FAN installed, and no other wires on the MB. In that condition if it won't post then it's time to replace either the PSU or MB. (It could be the CPU also, but rarely is).

Do you have a second PSU you can swap in ?

 

[Quinnens]

Make sure (again) both MB power plugs (the 4/8 and the 24) are firmly installed.

I did this like 10 times, before breadcrumbing, after breadcrumbing, between tries while breadcrumbing...

Can you blow out the x16 PCIe slot you used to make sure you didn't push dust down into the slot shorting it. Use a can of compressed air.

That's a good idea, I'll try this one today.

it's time to replace either the PSU or MB. (It could be the CPU also, but rarely is).

Do you have a second PSU you can swap in ?

If it's the mobo or the CPU, I'll freak out - I got both of them bad off factory in the beginning, replaced them, and then it was fine...
We have another PC with a PSU, but I don'f know if it's powerfull enough.

Thanks for your suggestions!