Steve you are correct. The Application Data folders are hidden by default.

Kelvin you can use My Computer or Windows Explorer to unhide the folder.

Open either and then click on the Tools menu.
Click on Folder Options... (at the bottom of the popup)
When the Folder Options dialog opens click the View tab along the top of the dialog.
In the Advanced Settings windows click in the Show hidden files and folders option.
Click OK button.

You can now see the hidden folders. Follow Risto info about where to find the Application Data folder and the file to remove.