Tried to update OS and now I just get code gibberish on start

Question

I was/am on Mac OS X 10.6.7. The 10.6.8 update had downloaded, but I hadn't installed it. I decided to go ahead and do it today, along with a few other updates (such as iTunes). The OS was asked me if I wanted to Install, I said ok, it said I had to restart, I hit "restart". When it restarted, here is what I got:
The small little box in the middle tells me I need to do a hard restart by holding down the start button on the machine until it turns off, then restarting. I do this, and I get the same screen over and over.
Is my OS gone? Do I need to do a clean install?

Answer 1

Yes, I would do a clean install:
Drive Preparation and Reinstall
1. Boot from your Snow Leopard Installer Disc. After the installer loads select your language and click on the Continue button.  When the menu bar appears select Disk Utility from the Utilities menu.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area.  If it does not say "Verified" then the drive is failing or has failed and will need replacing.  SMART info will not be reported  on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the process has completed.
4. Quit DU and return to the installer. Install Snow Leopard.