Motherboard: MSI 760GM-P23 FX
Integrated graphics (on MoBo)
CPU: AMD Athlon II x4 640
RAM: GeIL Pristine 4GB DDR3
Case/PSU: TOPOWER TP-4107BB-400
Is not POSTing, no video output, no beeps. When RAM is removed, 3 beeps. I have tried removing and replacing the CPU and all the power cables with no change. Resetting the BIOS (by removing and replacing the battery) did nothing as well.
Is there something I'm forgetting (1st time building from components), or could one of the components be bad?
EDIT: New development: with CPU and RAM installed correctly, it will turn on lights and fans (still no POST) and after running for a minute or so it will turn off and the PSU will make a buzzing noise that ceases only when unplugged.