I have a problem with my motherboard/computer. My power supply blew and i got a replacement sent, when i connect it it doesn't power up, the power supply is fine as i had it checked, but when i don't connect the ATX 12v connector the power supply powers up but windows don't load up. For those that aren't sure where the ATX connector is, when connecting the power supply, you have 2 connections that attach to the MB, a rectangle one and a small square one, the ATX is the small square one. It seems like there is a problem with the connection on the MB, is there a way i can get around this or do i need a new MB for this one connection?

i had it checked, but i never tried a different PSU in my computer.