How do i switch my func key so its F1-12 by default instead of misc (brightness, volume etc)?

I bought a new dell laptop inspiron 1545. By default F1 is to switch monitors, F5 is brightness up, etc. I use the F1-12 keys extensively with multiple programs i use. How do i set the laptop to use the buttons as F keys instead of requiring to hold down Func to use as f keys?|||Your Fn key is stuck. It's usually blue or grey and to the left of the space bar.