Chances are that you have the Windows Desktop Update installed and you are running IE 4.0.

In any case, try the following:

01. CTRL+ALT+DEL

02. Press Task Manager.

03. File / New Task (Run...).

04. Type regedt32 into the Open box.

05. Click OK.

06. Navigate to:

      HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CabinetState

07. Select the Settings Value Name in the right hand pane and press Delete.

08. Registry / Exit.

09. CTRL+ALT+DEL

10. Shut Down and restart Windows NT.

11. Install IE 5.0.