"I was trying to use the re-install option, but when I get to the window that says; Select the disk where you want to install Mac OS X,.."
The reinstall is supposed to be initiated while booted up from the recovery partition. You will need a network connection and a lot of time.
If you have access to another Lion machine with a Firewire port, you could boot your problem machine into target disk mode and connect it via firewire to the other machine, then try installing the OS X 10.7.4 combo update from Apples support downloads. That tends to be the fastest route to recovery if there is nothing otherwise wrong with your machine.
I say, "if there is nothing otherwise wrong with your machine" because your reference to 'The "Untitled" option,..' is somewhat worrying. Generally the target hard drive's name appears instead of "untitled".
Better let the Genius Bar tech have a look at it.