I must admit I'm not quite sure what the power bar is butI'm guessing that it is what I call the system tray - the icons to the right of the task bar. There is no single way of closing these programs. In some cases, a right click will provide a menu with that option, in others, you may have to open the program and select an option from there. If it is a separate bar, again try a right click. Ctrl/Alt/Del may also enable you to shut the programs or bar down.

Jon