i want to restore my imac so it "like new." because its running slow. last month when i restored my mac mini it got 99% but never finished. had to take it to the apple store so they can restore it. i dont want to do that with my imac because it's big. MY QUESTION IS, is there a way to tell if your snow leopard disk work and theres no problems with it be4 i go throughout the restore process.