|We definitely need more info to really help you. |
What exactly do you mean by 'and other devices'?
Are you sure that the hard drive is properly connected?
Have you tried using a different hard drive?
Have you tried booting from your Windows installation disc?
Do you see anything on your screen when you boot up?
Are you able to get into BIOS?
You say all of your fans are running, are they through the mainboard or the power supply?
Which power supply do you have?