I can't get the blue function key to work on a Dell Latitude E6510. I am desparately trying to get the F8 function to work which switched the video output between the laptop screen and an external monitor.
If the laptop has had an OS installed on it that was not the original image then this can occur. At least is has occurred when I installed a non standard Win 7 install on my Sony. If this is the case see if there are drivers on Dell's website that may resolve the issue.