Official GIGABYTE Forum

P55 Motherboard-I5 750 Processor-was working now it will just keep rebooting

Not sure what happened. I thought I successfully installed a P55 motherboard in an ATX case last week. It was working. but needed a little cooling help.
I installed a new case fan..and then it stopped working-it turns on for a second or so and then reboots..keeps doing that until I unplug the power supply.
I put my old AMD board back into the case and it works fine-not the PSU or other component. I put the old case fan in and that did not solve it.
The lights on the MB light up for a second as well..Any idea what I can do other than RMA the board? Everything else is connected correctly