101 Mac Keyboard Shortcuts

Hold down Shift key during computer startup and don't let go until you see a message "Welcome to Macintosh. Extensions off." 
You Mac will not load ANY extension or control panel. You'll have more memory left, but you will not be able to print, play movies, connect to a network and run an application which required extension.
Try This When:
1. Your Mac is frozen during computer startup. This will allow you to get to the Finder to remove extensions or control panels that you think are causing the problem.
2. You need access to your computer ONLY to copy a file or to do a simple task. 
3. You want to have more memory to run an application which do not required an extension. 

Want to quickly send a sleep-capable Mac to dreamland? Simple enough.
Press the Command, Option, and Power keys and say nighty-night to
your computer. Press any key to wake the Mac again. 

Hold down Command + option during computer startup and don't let go until you get a message "Are you sure you want to rebuild the desktop file on the disk "disk name" ?"
Result: 
You Mac will rebuild the Desktop files.
Try This When:
1. Documents fail to launch after double-clicking.
2. Custom icons are unexpectedly replaced with generic document or application icons.

Hold down Command + option + Shift + Delete before you see the "smiling computer" during computer startup. Let go after you see "Welcome to Macintosh."
Result: 
Bypass startup drive and boot from another hard disk or CD-ROM which contain system software.
Try This When:
1. You want to boot from another hard disk or CD.

Hold down Command + option + P + R during computer startup. Let go after you hear the "Chime". 
Result: 
You Mac will zap the PRAM (Parameter RAM). Settings like mouse speed, memory disk cache, and keyboard repeat/delay repeat rate will be reset to factory (default) setting.
Try This When:
1. You have try all the method to solve problem.
2. Application always crash.

Hold down Command + option + T + V during computer startup.
Result: 
Makes your AV Mac switch your Mac's screen display from a monitor to a connected television set. Work on AV Mac only.

Hold down C key during computer startup. Let go after you see "Welcome to Macintosh."
Result: 
Forces your Mac to bypass the startup disk and startup from CD-ROM. But you must have System software inside that CD. Works on PowerPC only.
Try This When:
1. You want to boot from CD.

Hold down Command + Control + Power Key.
Result: 
You Mac will restart and ALL UNSAVED CHANGES WILL BE LOST!!
Try This When:
1.Your computer crash and you can't move your cursor.

Hold Down Command + Power Key. When the programmer dialog appear. Type "G Finder" (Without the Quote) and press return.
Result: 
You Mac will quit the current application and go to the Finder. ALL UNSAVED CHANGES WILL BE LOST!! If you still can not quit the application after a few tries. Restart your computer. Please remember that even if you manage to get to the Finder YOUR MAC MAY NOT BE STABLE ANYMORE!
Try This When:
1. Your computer crashes but you can still move your mouse and you do not want to restart.

Hold Down Command during computer startup and don't let go until you see the message "Welcome to Macintosh." 
Result: 
Boot with Virtual Memory off (if you turn on Virtual Memory).

Hold down Spacebar during computer startup until you see Extension Manager's windows appear.
Result: 
Extension Manager to boot up but you must have EM Manager installed. If you install Conflict Catcher™, your Mac will open Conflict Catcher, not Extension Manager.
Try This When:
1. You want to enable/disable an extension or control panel.

Hold down Command + Option + X + O during Mac Classic boot up. Let go after you see the message "Welcome to Macintosh."
Result: 
Mac Classic will boot up using System software inside the ROM running System 7.

Hold down the Mouse Button during computer startup to eject the floppy disk.

Hold down Command + Option + ESC to Force the current application to Quit. 

Hold down the Power Key to bring up dialogue box for shutdown/sleep/restart. You can press R for restart, S for sleep, ESC for Cancel and Return to shut down.

Hold down Command + Shift + 1 (or Command + Shift + 2) to eject a floppy disk

In OS 8.5 you can easily switch among Sherlock's Find File, Find by 
Content, and Search Internet tabs by pressing Command-F, Command-G, 
and Command-H respectively.