Try a new hardware platform or different software!
It's also possible that your attempts to hack the system have damaged
your hardware. Overclocking usually generates more heat and
semiconductors don't like being overheated!
Presumably you have done a "hard reset": I can't remember procedure for
Zire but its something like hold down reset button and switch on, or
just hold reset button for a long period.
Restores everything to 'factory'. You have to re-install your apps but
that isn't difficult. All your palm data (contacts etc) will reload
when you sync but to be doubly sure set hotsync to 'desktop overwrites
handheld' first time you do it.
If that doesn't work, then all I can say is you have discovered first
hand the risks involved in hacks and overclocking, good job it was an
inexpensive bit of kit.
--
Richard C