/dev/hda1 - This is the CF card (first partition thereof in fact) which is where the microdrive is mounted. Your sd card would be /dev/mmcda1, but as you say, you can\'t get your Z up and running anyway so this is a mute point.
You say you\'ve tried booting without any cards and it still doesn\'t work. Not a good sign imo, what you describe is identical to what happens when a flash goes wrong.
That said, although you\'ve taken the battery out, the backup battery may have protected the memory. I\'d try pressing in the hard reset button (inside the battery compartment), then try starting up again (cross fingers).
If that doesn\'t work, though I\'m not sure, I would guess that your only course of action is to reflash, though I really can\'t see that you\'ve done anything to harm the base system so I\'m a little confused.
Si