Why is my iPod classic corrupted and not restoring or formatting?

I just purchased a 30 gb ipod classic 5th generation with a weak battery and a dark spot on the screen. It played fine when I first tested it but the hard drive would make clicking noise when turned on and changing tracks. The battery only lasted about 4 hours. I was going to change the battery and screen and thought I might as well replace the hard drive as well since it might be going bad. So I upgrade the 30 gb hard drive with a new 60 gb along with a new lcd screen and 850 mAh battery and thick back cover. Used the same motherboard which was working before and the headphone jack and hold switch that was on the used 60 gb cover. No problems with the changeover and putting it back together. When I turn it on it says to connect to computer and use itunes to restore. I connect to computer and open itunes. The ipod doesn't show up. I unplug it and says the ipod is corrupted and needs to be restored before using with itunes. So it only recognizes it when I unplug it. The computer shows it as an ipod when plugged in and says it needs to be formatted. When I try to format after a minute or so I get a message that it was unable to format. I try a few more times to format but get the same thing. So what could the problem be? The larger capacity hard drive should be compatible. They go up to 60 gb. Should I try to go back to a 30 gb?