You have not by any chance bent one of the pins on the drive or the board for the IDE cable as that well/may cause the light to stay on (like it would if you put the cable in a floppy drive the wrong way round)
Is it just loading the bios then not loading the OS .(having to guess thats what might be happening as you have not said if it is loading the OS as i have had the same problem once before) Is the HD spinning up if yes it might be your IDE cable if you have a spare cable try changing the HD one...
That all depends on what you are listening to if the music starts of with a lot of bass (or with a cannon going off and there are some that do) and the iPod is set at full blast kiss your ears good bye,by the time your brain gets over the shock and tells you to turn it down/take the headphones...