Sorry, I've searched for answers, but can't find any. When I go to install Snow Leopard, the only disc it finds is my external, which I use Time Machine for. It won't find either of my internal ones. Plus, it gives me a yellow exclamation point sign on my external anyways. I have a Mac Pro, 2 x 3 GHz Quad-Core Intel Xeon I have 4 internal HDs, but I made it into 2, by striping them. I have never had any problem with any installation. Thank you so much for any help.