If you need to either restore or reinstall the OpenSolaris OS, do the following:
Restoring the OpenSolaris OS. You should back up the data on your workstation on a regular basis and store the backup in a safe place. Using the built-in RAID capability of your workstation will also help avoid data loss and down time. If you need to restore the operating system on the boot drive, you will need to use the last known good backup image.
Reinstalling the OpenSolaris OS. If you do not have a back up and need to reinstall the OS, do the following:
The installation overwrites all the software and data on the selected target boot disk.
Download the OpenSolaris (x86/x64) LiveCD image from the web:
Follow the instructions in the Getting Started With OpenSolaris 2009.06 guide at: