Haalp! imac related. Won't boot past apple logo

I was in the middle of a software update(10.9.4) and the screen went white. After a while it shut off.

Now it won't get past the apple logo boot up. :(

Here are a few tips to try:

http://macs.about.com/od/MacTroubleshootingTips/tp/Top-10-Troubleshooting-Tips-For-Mac-Startup-Problems.htm

Thanks! That helped. I had to format the hdd, and install the original software. After that I updated, without any issues.