Answer
This question was answered on June 17, 1999.
Much of the information contained herein may have changed since posting.
The icons in the system tray, for the most part, represent programs that are running and therefore consumming resources like memory. Depending on the specific programs they may use more resources as computer-on time increases contributing to out of memory messages. When memory errors occur applications may stop responding forcing you to use the Ctrl-Alt-Del to close each active program.
How you take items out of the system tray varies with the program, but here are some general suggestions: 1)try simply right clicking on the icon, this may present a close or remove option; 2) open the program and look for a properties or preference option and deselect the system tray setting; 3) if 1) & 2) fail to work uninstalling the software may be your only other option.
If these options do not work for you please write us back and list what programs you have with icons in the system tray.