Hi, my friend gave me his macbook a1181 model , without a back up disk. so i had to borrow the disk from my other friend that has the same model . the backup disk has mac os x 10.5.6. i tried to reinstall the operating system to just make it like new.. so i restarted the macbook and press c with the cd in my external samsung optical drive because the internal optical drive doesn't work. i booted from the cd then i got a message saying that "os-x cannot be installed on this computer" so i went to disk utility and clicked on the internal hardest then erased it . now when i restart the macbook i get a question mark icon flashing and when i connect the samsung optical drive and press c i get a grey screen and nothing changes afterwards(i left it for 30 minutes) .. is there a solution for what i have done? i appreciate the help because i need this laptop for work after the weekend.