OK, I've searched for the answer to no avail so here it goes: I am currently using my MacBook Pro with Leopard. I'm no computer genius, but I believe it's possible for me to install OS 10.4.9 (the one that came on my computer) on my external HD. If I do this then I should be able to boot from it and it would essentially be like having two different computers that are independent of each other. I booted from the install CDs that I got with my computer and proceeded to target my external for installation. After installing the first CD, my computer restarted w/o asking me anything about the second CD. I booted from my external HD only to find a black screen with white letters that behaved essentially like the Terminal in the Utilities folder that refused to restart or shut down. Curiously, after booting from my usual internal drive, I opened Disk Utility to erase my external drive and noticed that its content was the same as the installation CD's. Surely somebody has tried doing what I have successfully in the past, where did I go wrong?