Which CPU power cable did you connect? The 4-pin is not enough for the quad-core you have, you should be using the other connector (you would have to have pulled the plastic cover to connect it properly)
Since you can hear the HDD's spin up, It is not as likely that the psu is totally bad. But then, it could be. We need some other tests.
Do you have the LED on the motherboard lit up when there is power on at the PSU?
Did you use the q-connectors?
Have you disconnected the main power cable from the
mobo and reseated it?
Did you reseat your video card?
Does your system even do the single beep anymore?
Okay, let's follow the system.
PSU, not much yet to tell *unless yours has a fan in it*
Mobo, check all connections to the
mobo (power first, RAM, Video, HDD's/CD/DVD/Floppy data cables, front panel connections, any other PCI slots.
On the Video card, You do have external power going to the card? Is it plugged in well?
PSU - others (check the psu connections to the HDD's/cd/dvd/floppy drives and video as well as the processor itself.
RAM: Again, have you pulled it out and reseated it? I doubt chip creep would be a problem yet. But loose is possible.