Regardless, this is pretty minor with regard to security. This option may not be available on browsers other than Safari. Or, you can click on File and select Close All Windows in the drop-down menu. This shortcut should work on most browsers.
But it's easier now, say, to pull an alley-oop, in which the attacker might install malicious code remotely using a nonauthenticated exploit, and then convince an unauthorized employee over the phone to reboot the server using one of these methods. The keyboard shortcut to close all windows on a Mac is option + command + W.
An Open Firmware password is much stronger against this kind of attack. Of course, this is a very small measure of defense. Previous security guidelines advised against enabling these buttons, as a small measure of defense against two general scenarios: in one, the attacker has modified binary code on the system by remote means (buffer overflow, filesystem tricks, etc.), and needs to reboot to apply the changes in the other, the attacker wants access to protected data on the machine and intends to reboot from a custom hard disk or CD (think: Knoppix), or put the machine in TDM mode with their laptop. There is *always* some risk associated with allowing a machine to shut down or reboot. And, obviously, you must have unchecked the "Show the Restart, Sleep, and Shut Down buttons" option in that same area.] I just think this seems like a very handy timesaver - note that you must have the "Display login window as" area of the Login Options section of the Accounts preferences pane set to "Name and password" for this to work. If this is a home machine, more than likely the power button on the CPU will be reachable, which would let one do the same thing (without being at the login screen, for that matter). If this is a public kiosk machine, the login screen will be unreachable. Some may claim this is a security hole of sorts I don't believe it is, as being able to shut down or restart from the login screen implies that you can actually reach that screen in the first place. [ robg adds: While testing this one, I found you can also use >sleep to enter sleep mode. As far as I can tell, this only works in Tiger. How do you shut down or restart your Mac when you are at the login screen and the Restart and Shut Down buttons are disabled? It's simple just type >shutdown or >restart as the user name, then click the Log In button. To reset PRAM, follow the steps below: 1.
Resetting both PRAM and SMC might help you fix the not working keyboard. First, I must give credit to my colleague for finding this today. SMC (System Management Controller) in your Mac is responsible for cooling fans, keyboard, and more processes.