I'm new to Macs..... So I only have an old Powerbook G4. I'm trying to learn Mac OS X, mac hardware, etc....I installed Leopard there first and it booted from the hard drive...But it was very slow. So decided to install Tiger and found bootable tiger retail full version. When Install tiger using that ....installation process completes successfully and restarts. at that point it does not detect the hard disk as a bootable device...Checked hard disk with Disk utility and it says hard drive is "ok". So I tried re-installing Leopard and now I get the same problem with that too. Could someone please help me out here..Thanks you in advance.