Intel PC keeps rebootinfg after 18 seconds

[Rouche]

I bought a new tower, then I moved everything from my old 1 to the new one. when I switched it on it reboots after 18seconds

 

[Tmagic650]

Carefully remove everything and start over, making sure you properly install the motherboard and connect the power supply to it

 

[Rouche]

When I plug in my “geforce gts 250 duel dvi” the pc will reboot after 18 seconds, when I put in a diffrent graphics card it won't reboot the pc runs normaly.
When I put my geforce gts 250 in another pc it works. So there is no problem with the pci-e slot or the graphics card

 

[Tmagic650]

Are you connecting the power supply to the video card in the new build?