So, this box (Quit All Running Processes) pops up? What now?
This box indicates there is important software that needs to be installed. If you are ready to install, you can simply click the quit all button.
If you quit all, or if this came up when you you had no open programs, it would begin a count down, such as in the picture below that tells us, "Installation will begin automatically in 113 seconds." If you don't want to wait, you could click the Start Installation button.
Let's assume you do not have time for this to install at this moment. You can delay it, and it will give a time. You can change the delay to as long as 2 hours.
After the period of delay (anywhere from 15 minutes to 2 hours), the box will come back, at which time, you may choose either to install or delay again.
During installation, you may see a gray box over a black screen with words to this effect: