Possible bad psu? OS realted?

This is a long story so let me get started.So this morning I installed the windows 8 consumer preview and everything didnt go so well. I have to install it like 4 differnt times before it finally worked, which I,m sure caused a lot of problems to my system. I get it working and then the new RAM I ordered came so I decide to put it in giving 8GB. I gurned my system back on and booted up.I configured the new OS to my liking and reststed my computer to save all changes and downloads I made. I tried turning it back on and I notice none of peripherals were working, keyboard, razor naga, monitor, nothing. The monitor is a 24" samsung led which just pulses a read light meaning that it isnt reconizing the dvi device connected to the computer. I turned off my computer again and turned it back on and it worked....then it turned off again and it wont work at all anymore. Everything turns on, fans etc but noe of my mice or keyboards and monitor still eont turn on. I have come to the conclusion that my power supply has gone bad out of no where. I just want to comfirm with other people that is what the peoblem is. I also want to point out that I flashed my bios this morning and it seemed to work, no problems at all so I dont think that is the issue. I am running a core i3 gtx 560 and two sata drives and blue ray drive. Could it be a wattage issue? My power supply is 650w, but I never had a wattage problem before.Any and all help is greatly appreciate so I dont go and waste amother $100 on another psu tomorrow.