Shutdown during Itunes update, now won't let me login

So I have a new macbook that's been working great until now. I installed updates for itunes and waited to restart my computer. later that night I went to shut down the computer and it started to re-install the itunes update. Instead of waiting, I held down the power button to shut down. The next day I went to start her back up and it comes up with the origonal background and a login box that I had never seen. It had my user name and a spot for the password, but my password would not work. I have it at a Best Buy and the Geek Squad is working on it but they are stumped. Does anyone have any idea??

Solution

I had the same problem as you. After about 4 trys of fixing it (I kept reseting my password over and over again) it still wouldn't work! So I went to software update and it said that there was a Mac OS update. I clicked on it and updated my computer. After it restarting, I went straight to iTunes and I was able to log in perfectly.
So just see if there are any updates. =]