Help!! Accidentlly erased my hard drive, won't work

[mikeytriangles]

I just got a used macbook air, and went to reset it to factory based off memory, pulled up the disk utility, then went to erase macintosh hd... i thought this would wipe everything and let me reinstall lion for a fresh start to transfer everything over from my pro, but instead i got nothing, and now just a blank screen with question mark. can't get anywhere, please help!! it's my wife's birthday present and today is her bday

 

[mikeytriangles]

so anyone know how i can natal an operating system on the air with no disk drive?