Macbook Air Dual boot, OS X boot fail

Hi,
I have a dual boot installation of ubuntu 14.04 LTS 64 bit & OS X Lion on a mid-2012 Macbook Air w/ 4GB Ram, i5 1.6GHz Quad core, 128GB SSD. Ubuntu is on a 15GB partition. Ubuntu was installed from a USB stick, this machine has no optical drive.

Ubuntu is running fine, and is what I have been using since I installed it. However this morning I attemtped to start OS X for the first time since installing ubuntu, and OS X will not boot. After choosing OS X from the rEFit menu, the screen goes dark (not like the computer is completely off, the display still has power) and that's it, OS X never boots.

I read some instructions about removing rEFit, but that involved working in OS X, and I'm not sure if that;s the direction to go regarding this issue anyway, so I'm asking for your advice here.

It won't be a disaster if I can't recover OS X, but there is a file I was using under OS X, and I can't find it searching the partition in the ubuntu Files explorer, but I know the name of it and I know it is there somewhere on the OS X partition. But it didn't turn up searching in Files.

Thanks!