It’s a known problem. Try these:
1. Sometimes logging off and back on or restarting the computer clears the problem.
2. Click the Windows Orb (Start), type regedit, press Enter and navigate to registry key HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify. In the right-pane there are two entries: IconStreams and PastIconsStream, right-click and delete them, then restart the computer.
Create a system restore point before deleting the registry keys in case anything goes wrong.