"i just reinstalled everything on this new hard disk, while i still i have my back up stuff in the old root disk
(where the system files were installed ) and I mkfs-mount- fstab everything was nicely and neatly done, however, when i opened up my old disk , there is nothing there, besides lost + found "
It looks like either you or the installer ran mkfs against the old root disk.
Be prepared. Create a LifeBoat CD.