Please help me a new power supply or motherboard?

[juiceman15]

I recently purchased an hd5770 and it was working good maxing out games at 1680x1050 with fps above 60 but this morning when i woke up and turned on my computer the keyboard is not getting any power my power supply is 500wats so i turned on the monitor says no input check cable. i tried clearing the cmos.i checked the cables but i recently noticed a short in the power supply cable the one outside the computer.i tried different monitors,graphics card tried putting in my old 9400gt the fans would spin cpu,gpu the optical drive would open but i am not getting any power to the keyboard. The motherboard name is a gigabyte http://www.gigabyte.com/products/product… cpu, amd phenom x2 940 quad core 3.0ghz.4gb of ram,1tb western digital black hard drive,windows 7 64 bit so what do i need to replace? thanks guys

 

[juiceman15]

nope it does the computer comes on but my monitor does not receive anything from the gpu so i can not even see anything when the computer come on on my psu brand is omega 500 watts generic power supply. thanks