How to Fix Sudden Disappearance of System Icons in Windows

 You may face this issue while running Windows Vista or Windows 7 for the first time or after a long break. In most occasions, one or more of the icons listed below will disappear from lower-right corner of the Taskbar.

• Power Icon
• Sound Icon
• Network Icon 

Most probably, you will try to make it appear by going through Turn system icons on or off in the Notifications tab in Taskbar. But you will be shocked to see that the icon (which is disappeared) can't be selected.

(Here) Power icon can't be selected

There are two simple working methods (you can find more) you can try for making the disappeared icons re-appear in theTaskbar.

Method 1
The best working method is just Restart the system! This was the method worked for me, in such a situation.

Restarting the system is the one of the best working solution

Method 2

Step 1 
If it doesn't solved your problem, go to Windows Task Manager by hitting CTRL+SHIFT+ESC. Now select Processes tab and choose explorer.exe.

explorer.exe selected in Windows Task Manage

Step 2
Now click on End Process. A confirmation message will be asked an click End Process again.

Click on End Process twice

Step 3
Now, all the running process will be disappeared including the Taskbar. Click on File → New Task (Run...) in Task Manager.

Choose File>New Task (Run...)

Step 4
Type explorer.exe and click Ok.

Everything will be refreshed and you will be able to see your disappeared system icons again in the Taskbar. If this also not fixed your issue, please mind going through this article created by Microsoft experts. I hope you will get a solution from there.