Motorola

I recently got an MPx 220 and I have been having a couple of problems. One is showing a white screen before popping up the sub menu. The second thing is that I get an error message that says that I have too many applications open and that I need to close them, I don't know how to close and application (I am assuming that it is referring to the menu that runs along the top of the phone) except to hit the back button until I get to the home screen. This is very inconvenient especially when you are on the internet. Could someone pleeeeease help.