Escape (Esc) key: In some applications, the escape key will move you up one level in a programs menu hierarchy. In others, it will exit the program. Mostly these days, it doesn?t do anything.
Print Screen (PrtSc) key: This key used to send an image of the document you were working on to the printer, but it only works if your display is in text or CGA graphics mode. Some programs still use it as a way of capturing a screen image to save as a file.
System Request (SysRq) key: A descendant of the old IBM mainframe computer terminal keyboard, it stands for ?System Request? and was used to either reset the keyboard or change from one session to another. These days, ?Print Screen? and ?SysRq? often share the same key.
Scroll Lock: This key once kept the screen from scrolling, but most applications ignore it.
Pause: This key calls a quick halt to the action, and it still works. Move the cursor to the top of the page, hit a down arrow so the cursor starts sliding down the screen. While you are doing that, tap ?pause? and the cursor will stop. Many games respond to this key. ?Break,? which often shares the same key, does the same thing.
I hope this helps =)