So I'm trying to fix my friends Macbook Pro that he got in 2009. He was having trouble with it, so he brought it into a repair service that told him he had to replace his hard drive. I told him I could do it so he can save money. I took all the right steps to physically replace the hard drive. I'm currently trying to install OS X Snow Leopard from the install disc. When I get to the screen that asks what disc I want to install the OS on it doesn't list the new hard drive. I went into disc utility, tried to format and partition the drive but keep getting error messages that say "Input/output error" or "Can't allocate memory" One possible solution that I found was replacing the SATA cable but I figure that should be the last thing I try. I'm hoping it's a software issue. I have a USB thumb drive that when I plug it in gives me the option to install the OS on that. Should I try this? Would I not be able to use the disc after that? Can I install it on the hard drive from the USB after I do that? All advice is greatly appreciated.