Another flaw I found in Mac OS X. You cannot lock your Mac the way you can in Windows Vista.
In Vista, you lock your user or screen, you can simply click the lock button on the start menu. Your screen will be locked & if you have set a password then it will ask for a password to unlock it.
At this stage, another user can come & log in to his own account, & the previous users account will continue to run in virtual memory. The 2nd user can simply complete there work & log out while the first user will still continue to run.
In Mac, when you lock your screen, it runs a screensaver, now to unlock you move the mouse or press a keyboard. However, you cannot login to another user account while doing this. You can only login to the account of the user who locked the screen.
Windows way is much better cos you can continue to do your work like downloading etc, & lock your user while some other user can simply login & do whatever he wants.