New hard drive in early unibody 2011 MacBook Pro won't boot Newbie here!

I just replaced the hard drive (to a 1T senate SATA) in my MacBook Pro and upgraded the RAM from 2, 2GB cards to 2, 8GB cards.

Hardware install went smooth, backed up old drive to time machine &amp; made a USB of OSX for install on new drive.

I've gone in and reformatted the new drive with the proper settings (1 partition, journaled, etc...).

When I go in to boot up the system, the computer goes to apple logo grey screen and the loading bar comes up, loads to exactly the halfway point in about 6 minutes, then just sits there... For hours.

I've tried it many times always with the same outcome.

I need my computer for school TODAY!
Reboot the computer and hold down the option key so you can access startup manager. 

If you've already installed OS X, select your HD from the system.

If you NEED to install OS X, select your USB key and run the install

Another option would be to restart the system and hold down Command + R to enter recovery mode. Depending on your Mac model, you'll actually be able to install OS X from the internet. It will be the version you shipped with, but you can just follow the upgrade path to Yosemite.

And if you have to use your computer today, I'd just throw in the old hard drive and deal with this over the weekend