iMac 21.5-inch Mid 2010 won't boot into OS X after installing Ubuntu, will boot into grub rescue

So, as the title says, I have an iMac 21.5-inch Mid 2010 model and I installed Windows 8.1 with Boot Camp. After attempting to uninstall Ubuntu and Windows in Disk Utility (in OS X and Recovery) it would always give me an error, "Partition failed with the error: The requested size change for the target disk or a related disk is too small. Please try a different disk or partition, or make a larger change."

What I have tried:

1. I have tried resetting PRAM/NVRAM with Command + Option/Alt + P+R, nothing.
2. I have tried holding X to Start up from an OS X startup volume when the Mac would otherwise start up from a non-OS X startup volume. Using Startup key combinations for Mac, still nothing (did work before).
3. I have done things in grub rescue such as ls (lists partitions and disks) and attempted to boot back into Ubuntu.
4. I have tried holding Option/Alt to get into the startup manager, still boots to grub rescue.
5. I have tried holding Command + R to boot into Recovery, worked before, not working now.

What I can't do:

• Can't use another Mac to do anything such as target disk mode (no firewire cable).

My iMac Specs:

iMac (21.5-inch, Mid 2010) - Technical Specifications

21.5 inch, 3.06 Mhz, has OSX 10.10 installed with Windows and Ubuntu 14.04.2 LTS.

Solution 1:

Fixed after many days. I noticed that the keyboard wasn't initializing during boot so I picked up a new keyboard(something I didn't even think of at the time) and it initialized. I held the Option/Alt key and to prevent this from happening again I installed rEFInd.