Only sync a few megabytes at a time before dying

I recently replaced my hard drive because of this problem. I narrowed it down to being able to sync for a small amount of data at a time, then disconnect from my computer. If I try to do more it will return write delays on my laptop and reboot and go into "must restore" message. If a let it sit for 30 min and perhaps less without doing anything else, I can reset it to come back up happy, and I can see all of the music I have successfully synced again.

Do you think I still have a hard drive problem, or is it the logic card. Battery status is fine will go down if I leave on and charge up if connected, and appears to have no affect on whether my syncs are successfull or not.

Thanks in advance!