[G4] cant find harddrive

[Win werner]

guys - I have a real problem - I am running a G4 - two hardrives

the original one with the system on it an a lot of other stuff - it is ok
another hardrive - partitioned into 4 parttioned - I accidentally erased -
I think I erased it writing 00 over top - it does not come up on the desktop 
and I have no idea how to find it - and mayby restore data on it -
HELP would be greatly appreciated  - thank you
win.werner at sympatico.ca