I need some help please. I have been trying to locate the download for OSX Yosemite for two days with NO success. I go to the Apple store and see the Yosemite page, but when I hit upgrade nothing happens. I went to Utilities page and hit the "Get" button, again, nothing happens. I have the Update Combo but I need to first install Yosemite. I've check out ALL of the requirements, which my iMac meets and have down a complete backup via Time Machine. Any help with this will be greatly appreciated.