undo archive and install of leopard?

hi folks. i recently upgraded from tiger to leopard and have an issue with (it seems now) some of the macbooks hardware. i did a new archive and install on the recommendation of a genius bar guy and the problem is not fixed.

so can i revert to the 1st install? (from the "previous system folder") - the display calibration seems a bit wonky now.

if not, do i just throw away the 10gb previous system folder, and if so is there a similar folder left over from the initial tiger to leopard upgrade somewhere i should toss?

thanks for any help.