Hitting the "X" does not fully close applications
 

When I'm done using a software application they do not close all the way and it eats up my memory very quick. Is there a way that when I hit the "X" that the applications do in fact close for good? I have been going to "settings" > "system" > "Memory" > "Running Programs" > "Stop All". This process is very annoying. Any help would be appreciated!

This may seem like a dumb question, but I'm seeing that for some applications to work that I download I need to "Install the cab file", how do I go about doing this?

EDIT: I messed around a bit and I found out that I just place the .cab files in the windows directory and "install" them from the device...

Can I remove the .cab files from my device after I have installed them?

Yes

Please search before posting these are all very basic questions and have been asked many times. Many if these type of questions can be answered by reading the FAQ sticky found HERE <-Link