Is this a HDD or logic board issue?

My iPod 5th gen video 30GB starts with the sad iPod face or the connect to iTunes support screen on start-up. It is recognized by my PC and iTunes will restore and sync (w/ 400+ tunes) with no problems. BUT, it will freeze during 1st song playback, click-wheel is unresponsive except for shut-down. Then again either of the 2 above screens will appear on start-up. Occasionally, it will start normally and then still freezes. I've replaced battery (not as a solution) and HDD flex cable which I thought was the problem but wasn't. I think it's the HDD and I'm waiting on a ZIF:USB adapter to check it out. Am I on the right path? I think it's the HDD and hope it isn't the logic board... what do you think?