my macbook air wont start.

Hi, My Mac Book Air failed on me and when you turned it on it went to a file on a grey screen flashing with a question mark on it? I held down Comand R and it went to internet recovery mode that worked fine after a while it went to some OS X Unilitys and i clicked Install OS X Mountin Lion but it wont it just stops. i need help i need to this laptop for school.