Hi, I just bought a new 2010 Hitachi hard drive (250GB) to replace the old 2008 Fujitsu hard drive (80GB left) in my Macbook. The seller told me that the new drive contained a fresh install of Mountain Lion and that it should work perfectly on my Macbook, which currently has Leopard. When I tried to install the new hard drive, a crossed circle showed up on the screen and nothing else happened. I turned it off and tried again, this time holding the Option key. Same thing again. Tried again and held down the Control key this time. Two folders showed up, and when I clicked on either one of them, the same result again. I am a complete newbie to all of this and need help. I am not sure whether to return the hard drive or keep trying. Any suggestions?