ClickOnce installations are installed to a users directory. Depending on the version of Windows, ClickOnce is installed in different file paths.
For Windows XP, ClickOnce applications are installed to:
C:\Documents and Settings\UserName\Local Settings\Apps\2.0\xxxxxx\xxxxxx\
For Windows Vista and Windows 7, the ClickOnce file path is:
where xxxxxx is a randomly generated folder name.