Answer to "What is the procedure for replacing my Dell laptop's keyboard?"you can visit '''Dell Technical Support''' to resolve your issue. you will get a manual guide here from which you can easily learn about replacing dell laptop’s keyboard.
Answer to "Why does my browser crashes after a few minutes of usage?"Browser are computer programs when an unexpected error condition occurs, and on that time it is handle by existing code..... in many cases it happen that browser try to make disable plugin untill the activation of actual plugin. Mozilla Browser Support