As my heading stated, and I will know expand, when you type certain keys you get adverse reactions. The "f" key generates search. "v" generates a "v+.", "back Space" generates a bracket
See if any of your function keys like Alt, Ctrl, Fn are stuck. Hit them a few times pretty firmly, maybe take them off and reseat them. I'm using a MS wireless keyboard now, and the F key has an alternate "Find" function, looks like in your case you have something stuck where it's always on.