Shutting down

Question

For some reason, the 'shut down' in the drop down apple menu doesn't respond. neither does 'about this mac' but 'sleep' does.
I haven't dropped anything on the keyboard, and there's no other reason I can think for why these suddenly stopped working.
Can anybody help me here? Or can you suggest another way of shutting down my computer safely without using the apple drop down menu.
cheers
angela

Answer 1

There are keyboard shortcuts you can use; refer to Mac OS X: Keyboard shortcuts and the more extensive Magical Macintosh Key Sequences
Holding down the control-eject keys brings up the restart/sleep/shutdown dialog
command-control-option-eject will close open applications and shutdown the computer
Failure to shutdown when commanded can be caused by a background task that won't quit gracefully. Have you installed any software recently, especially scanner or all-in-one device drivers? Those are known to cause trouble with sleep and/or shutdown as they use a Unix daemon program continuously running to check for someone pressing the scan-to-computer button on the device. A similar problem cause is a defective USB peripheral or cable causing either a signal short or spurious signals on the USB bus inside the computer, which can trick the computer into thinking it still needs to wait for some process to finish.
You note that "About This Mac" is not responding; that could be caused by a third-party kernel extension interfering with the OS. Non-Apple programs that install their own icons into the menubar have been reported to cause problems. Do you have any third-party icons in the menubar?
A quick way to check for likely sources of the problem:
First, remove all USB peripherals and cables other than the Apple keyboard and mouse. If that fixes the problem, add devies back one at a time, testing after each, until you identify a device/cable pair that's suspect. Swap a known-good cable into that pair to narrow it down to the device or the cable.
I fthat doesn't solve the problem, move on to the second suggestion: Start Up in Safe Mode (with only the keyboard and monitor attached). If the compute then behaves as expected, you'll need to examine what's in the Mac's StartupItems folder (in the Library folder) along with third-party System Preferences panes (view System Preferences by categories and look under "other"). If it's not a hardware issue, some software installed or updated recently is the likely culprit. note that this can include the OS itself; sometimes, previously-working third-party extensions and programs will break under the OS updates. Check the third-party program's publisher websites for updates.
Good luck!