When it’s time to clean out a crowded directory, learn these file selection shortcuts for maximum efficiency:
- Hold down the Ctrl key and click to select or unselect files one at a time.
- Select one file, then hold down the Shift key and click on another file to select all files between the two you selected.
- Press Ctrl+A to select all files.
Here’s a shortcut that most people don’t know about. Say you have a folder that’s packed with files and you want to move or delete a large number of those files while keeping just a few. Select the handful of files you want to keep, and then choose Edit, Invert Selection. All the files in the folder except those you originally clicked on are selected and you can go ahead with your file operation.
Ed Bott 
I never noticed inversion. D’oh! I thought that inverted the file order for some reason.
Now, if only I knew how to do that in Vista. Anyone?
Chris, the option is still there in Vista. You’re just not noticing it because the menus are hidden. Tap the Alt key to make the menus visible, then click Edit, Invert Selection.