I am trying to do a clean install with Yosemite as I have had some bugs with the previous version that carried over. I have made a bootable install disc on a thumb drive and am ready to try it. The question I have is that I have two hard drives on my iMac, the 250GB SD Drive and a 1TB normal hard drive. I have all my documents, pictures, music, ect. located on the hard drive. On the SD drive I just have the OS installed. When I do to install, I know I am supposed to erase the drive so it's a fresh install. If I choose to erase the SD drive and reinstall, will I lose everything on my other drive or will it still be there?