At some point my system icons disappeared from my system tray (the little tray at the left edge of the Windows task bar).  Here is what I wanted it to look like:

I found may posts and complaints about this problem spanning XP, Vista and now Windows 7.  Most said, try this fix (a variety of suggestions)…it may or may not work.  Most folks said they could restart their systems and the icons would come back.  However, restarting did not work for me.  And besides, restarting a system is a disruptive and time consuming process.  I wanted and needed a better solution. [more]
 
At this point I have restored my icons and they have remained visible for 3 or 4 days.  In those days, there have been a couple of restarts and a shut down – I hope they are fixed.
 
I actually did a couple of things, reconfigured local group policies and also made a couple of registry changes.  It appears that it took both fixes together to restore my icons.
 
To change local group policies, enter gpedit.msc in "Run" or as a command line entry.  You will see the local group policy window:

Notice, in the screen shot above, you navigate down to "User Configurations," "Administrative Templates," and "Start Menu and Taskbar."  There the "Remove Clock…," "Remove network icon," "Remove batter meter (my icons are for a laptop with a battery)," and "Remove volume…," were all listed as Not configured.  According to the information I found I changed all the settings to "Disabled."
 
I also changed two Registry entries.  [All the normal warnings apply about being careful as you click around in the registry.  Any false moves while in the Registry can really mess things up.]  Having said that, use Regedit (entered in "Run") to be able to edit the Registry as follows.
 
Locate and click the following registry subkey:

  • In the Details pane, click the IconStreams registry entry.
  • On the Edit menu, click Delete, and then click Yes.
  • In the Details pane, click the PastIconsStream registry entry.
  • On the Edit menu, click Delete, and then click Yes.
  • Exit Registry Editor.

Restart the Explorer.exe process. To do these, follow these steps:

  • Press CTRL+SHIFT+ESC.
  • On the Processes tab in Task Manager, click the explorer.exe process, and then click End Process two times.
  • On the File menu, click New Tasks (Run), type explorer, and then click OK.
  • Exit Task Manager.

Then if you are using Windows 7 you need to be sure the icons settings are set to ON.  So follow these additional steps:

  • Open the Control Panel "Taskbar and Start Menu."
  • Under the Taskbar tab, in the Notification area section click on the "Customize" button.
  • In the Notification Area window notice the link "Turn system icons on or off." Click on the link and make sure the icons your prefer are turned ON.

Hopefully my icons will stay visible and this will be helpful for any others who have some system icons which disappear.