OS X Yosemite declining a reinstall because HDD is locked.

So I bought a brand new Macbook Pro - Retina Display. The issue started with the FileVault paused even when I put a power source for it to continue... After reading articles and everything else. The solution I found to end it was to Erase something about the HDD. So I ended up at the Disk Utility page and I technically erased and deleted the second HDD named as "Macintosh-HD". I have tried doing everything to reinstall OS X Yosemite. But since the HDD is locked I can barely do anything MAX I can go for is the terminal. Please help me out.