Option 1
Perform SFC(System file Checker) scan and see if it helps.
a: PressWindows key + X.
b: SelectCommand Prompt(Admin).
c: Type SFC / scannow and hit enter.
Option 2
In this situation, I suggest you to create a new user account and check if you still face the issue. To create it perform the steps mentioned below.
Press Windows key + R key, Run window opens.
Type control in the open box and click Ok.
Control Panel windows opens.
Click on User accounts and Family Safety.
Click on User Account and then click on Manage Accounts.
Now click on Add a new user and follow the instructions.
Now check if the issue persists in the new user account.
Option 3
How to Enable or Disable System Icons on Taskbar in Windows 7 and Windows 8