I purchased my PB G4 15" from a private seller in a booth at a local flea market about 2 years ago and the hard drive just went. I WAS running 10.6.4 i believe or whatever the latest Snow leopard. I swapped out the old HD w a larger one and went to install SL and wasn't even recognizing. Got ahold of a Tiger install disc, worked great. Tried SL and said i couldn't install. I am so frustrated!! All i want this comp for is my music and all the Torrents require 10.5 or later!! PLEASE HELP!!