Brand new psu installed but pc turns on then shuts off

[Felix345]

Hello, so I just got a GTX 670, installed it. Then I realized that I needed 2 6 pin pcis and my hpe 270f only came with a psu that had only 1 6 pin. So I got a brand new corsair 700w psu. Installed that but now if I turn it on the screen is black, no beeping or anything and it shuts off after like 3 seconds. Then it turns on again by itself and then off again.

So I disconnect the optical and hard drive connectors, still problem is there.

Any help would be appreciated as this is my first time upgrading a desktop.

Also the CPU connector that came with the new psu is 8 pin, but in my computer the plug is only 4 pin. But I read somewhere on the forum that that shouldn't be a problem.

Thanks

 

[Felix345]

Also I tried putting my old psu back with the old gpu and it works fine so...

 

[jay_nar2012]

How about the new PSU with the old GPU?

 

[Felix345]

Yea the new psu with the old gpu doesn't work, shuts off after a few seconds.

But even the old psu with my new card works and the screen comes on, just it says that I need to connect both pci-e connectors