Help me find my drive please!

Ok, I'll try and make this quick.  Someone gave me a 350mhz G4 (AGP
model) last year with a 10 gb drive about half filled. It was running
OS/X 10.2 but I didn't have any discs for it.

I then installed a second 160gb drive (about 130 gb visible) still
running the system off of the 10gb drive.  Over the course of the year
the 10gb drive became totally full, with only about 300mb free until
today when it became totally unoperational, blacking out and refreshing
whenever you click on a menu option.  This is AFTER moving every file
and application, mp3, and jpg to the newer larger drive.  File searches
couldn't even find any files larger than 100mb so there must have been
some weird invisible files going on?

Anyway, so today I had to get a project out but the computer didn't
work at all so I paniced and took the OS/X restore disc that came with
a powerbook I recently bought and loaded it up to the 160 gb drive to
establish that as the system disc.  It runs great now but now I can't
even view the other drive (which had my email accounts set up on it).
Not on the desktop, not anywhere!  How can I get back to being able to
use both drives but running the system off of the larger drive?
HELP!!!!

Thanks,
Frank