11.04 Editing commands in preferred applications renders arrow keys useless

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http://askubuntu.com – I, being rather noobish at things like this, ask for assistance in getting my arrow keys to work again... I'm runnning 11.04 in the classic environment (bout all my gpu can take). I took a look at the preferred applications to change web browsers, and sneaked a peek at the other things available. I saw that the multimedia's custom option's command was set to banshee. I don't have banshee on my system (I use rhythmbox). I deleted the words, for I felt they didn't need to be there. I left the selected application alone. Now whenever I use the arrow keys, (or the insert, delete, home, end, pg. (HowTos)