I have a XPS Studio 8100 desktop that has started to exhibited a new behavior. Several times I have come into the den to use this computer and it has been shut down. When I restart it I get a message that says something like"battery has reached its critical mass...."What battery is it referring to? This desktop is always plugged in. There is a battery icon in the system tray near the clock and the power plan is set to Dell. I have never changed the power options.Right now the battery icon is showing the charge at 100%. Again I am not sure what battery this is referrring to.