Apple Logo Only - Replaced Logic Board, Battery & Display

Hi,

I've had a fried iPod Photo 60GB (and previously the back light wasn't working either). After investigation I first replaced the logic board, but it didn't work though I could hear whirring noises. Next, I replaced the display (my original cable looked a bit "fried") and then the battery. Now I get the Apple logo continously, but can't get the iPod to be recognised by iTunes or my PC (tried to get it in disk mode manually but that doesn't work either, it will only show me the Apple logo). Any ideas what else I could try? Thank you!