Apple Mac Pro (Early 2009) - Manual (Page 81)

Chapter 4 Problem, Meet Solution 81
 One short flash followed by a longer off period: No valid memory.
 Three short flashes followed by a longer off period: Failed memory.
Problems with Software
When an application freezes or does not respond, Mac OS X provides a way to quit the
application without restarting your computer. Quitting a frozen application may allow
you to save your work in other open applications.
To force an application to quit:
1 Press Command (x)-Option-Esc or choose Apple () > Force Quit from the menu bar.
2 Select the name of the application you want to quit in the Force Quit Applications
dialogue.
3 Click Force Quit.
The application quits, leaving all other applications open.
If you have a problem with a software program
 Use Software Update to ensure that you have the latest drivers, bug fixes, and other
updates.
 For problems with software from a manufacturer other than Apple, contact the
manufacturer.
If you have a problem using your computer or working with Mac OS X
 Look in Mac Help (in the Help menu) for instructions and troubleshooting
information.
 For the latest troubleshooting information and software updates, go to the Apple
Support website at www.apple.com/support.