I have come across a problem with a few customers, at least a couple of machines, with the problem of not refreshing the System Tray ( right next to the clock 
) and the desktop icons.
You can simply solve this problem by following the steps below.
Lets start,
To refresh system tray icons;
HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify
find and delete IconStreams ve PastIconStream variables on the right pane,
Ctrl-Alt-Delete and open Task Manager, select explorer.exe under Processes and Finish Process.
Click Applications, select New Task, type explorer.exe and press Enter.
To refresh the desktop icons;
C:\Users\<user name>\AppData\Local
go to folder, delete the hidden IconCache.db file, and then restart the computer.
Enjoy.