Hello, so I decided to upgrade my graphics card for bf3 and my power supply. After installing the new card and the power supply the CPU power on all the lights go on and all the fans work but I dont get a signal on my monitor. I put my old graphics card in still the same problem. The PSU is a corsair cx600 and the graphics card is a geforce gtx 560 ti. Also the mouse and the keyboard don't work when plugged in.
Either you have a defective psu , which is possible even with something brand new. Or there is something not plugged in , you do have to be carefull with the connectors because some of the wires can pull out from the connector end. I would check the main power connector that plugs into the motherboard to make sure it is plugged in all the way and that all the wires are into the connector all the way.
Im trying breadboarding which was a method listed on here somewhere and trying to see what the problem is. I got the same problem from the previous psu so I suspect it is the mobo but I just hope it is something small.