Hi I had identical symptoms to Mr. Jackson above with my 30gb classic. It could enter diagnostic mode and show good stats for the hard drive, but never would go into disk mode. But luck was with me - it returned to normal after this sequence........... On wall charger, reset from the diagnostic menu, got the dreaded Apple logo again, waited until the screen switched to the battery charging symbol. Immediately pressed the center button and the Ipod woke up and gave me the normal menu ! All has been good since. Doubt this will work for all but worth a try - good luck.