lost data installation

[niels ruerup]

On a G4 DP I intalled YDL 3.0,  on a second hd .
Everything went fine, internet connection worked fine and so on..
great YDL!!!
But after restart into MacOSX (already installed on other hd) the
screen rested grey.
Disc Utility shows me a hd with all space free.
Propably the data has not been destroyd, but is not more readable?

Is there a posibility to rescue the data of this hd?

Thanks for any help!

(I will now reinstall YDL, MacOSX, MacOS9 on the new hd, and than look
for the "old"one mit the destroyd data)