You need to delete or rename the hidden file
C:\WINDOWS\folder.htt
Where C:\WINDOWS\ is your windows folder.

You can also turn off the view as a web page option.

Another option that keeps the view as a web page option is to copy the file
C:\Program Files\Folder.htt
to
C:\WINDOWS\folder.htt

Another option is to click on the menu option view | customize this folder.
Follow the wizard instructions and close the notepad document that opens.
Once done, click on the menu option view | customize this folder.
Select remove customization radio button and follow the wizard instructions.