Install Office 2010 – Microsoft Support
The symbol next to each feature indicates how that feature will be installed by default. You can change how the feature will be installed by clicking its symbol, and then selecting another symbol from the list that appears. The symbols and their meanings are as follows:
Run from My Computer The feature will be installed and stored on your hard disk when you complete Setup. Subfeatures won’t be installed and stored on your hard disk.
Run all from My Computer The feature and all of its subfeatures will be installed and stored on your hard disk when you complete Setup.
Installed on First Use The feature will be installed on your hard disk when you use the feature for the first time. At that time, you may need access to the CD or network server that you originally installed from. This option may not be available for all features.
Not Available The feature won’t be installed because it is not available.