OS X V10.7 Lion :: Restoring MacBookPro To Factory Settings?

So I recently purchased a MacBook Pro and used Migration Assistant to transfer my files.  I realized after that I should have transfered right at the beginning when I had the chance for Setup Assistant, because I have a lot of files that require permission from my other user account on my old MacBook.  I went to Disk Utilities, and there were two options to "Erase Free Space", some Toshiba thing and Macintosh HD (I am assuming was the hard drive that was transferred).  I pushed "Erase Free Space" and closed down disk utility, but it looks like it didn't delete my hard drive because all the applications and files are still there.  I am now reinstalling OS X Lion hoping it will bring me back to that first screen where it askes if i want to transfer from another computer.  Am I doing this right? I feel like I'm gonna mess something up and i've already wasted 5 hours already trying to fix my primary mistake of using Migration.