Excuse my getting technical but I think it is screwed, sorry couldn't help my self, but some times keyboards do die or get bunged up with food, debris, etc and effect the key response. The r & f keys are close enough for double pressure with heavy fingers or something jammed between the two.
You could try turning upside down an gently shaking it or use a compressed air can to try and clean it, other than that I don't know what else could be done short of plugging in an external keyboard.
