I recently just upgraded my mobo, cpu, and ram. Everything is installed correctly. When I power it on, nothing happens. And if it does by chance start up, it only flickers for about 1/2 a sec. The 24 pin is connected along with the 4 or 6 pin. Its not my power supply or the cord. Someone told me it could be the harddrive. They said it needs to be formatted in able to start up because I added new parts. Any suggestions as to what could be wrong?