Just an FYI, you likely had some file system issues preventing the machine from booting
(Command) Apple + S at the boot tune will enter into single user mode
at the command prompt type /sbin/fsck -fy > return
It will check the file system (fsck = file system check)
Likely will find some erors and correct them...
Once done type exit and it should boot into the full graphical user interface and desktop
Luckily OSX isn't anything like a re-install of Windows ( I use both and and don't discriminate or choose favourites), but and OS X install is painless compared to Windows
peace out