2009 MacBook Pro (5,5) won't load OS X installer from USB

I have a mid 2009 MacBook Pro that I believe to be the 5,5 model. I tried to install Ubuntu 14.10 over the old OS (OS X Mountain Lion). It seemed like everything went well with the install. When I went to reboot, however, I was greeted by a purple screen, but cannot get to a terminal or a log in screen.

No worries, I'll make an OS X Yosemite USB and boot to that. I used a newer MacBook to create a USB, but the 2009 MacBook Pro in question is not booting. The "Install OS X" option comes up when holding option at boot, I double click on the orange hard drive, and the apple logo comes up with a progress bar. The progress bar hangs at ~25% and did not move at all in the past 7 hours. How can I get OS X back on this machine?