Download offline installer, and install it twice or more times with different names (e.g. 5.2.0 and 5.2.0_2) and locations on disk (e.g. qt\5.2.0 and qt\5.2.0_2).

Open Control Panel and the list of installed applications, only Qt installation visible is 5.2.0. See the location where the installation points to, should be qt\5.2.0 but is actually qt\5.2.0_2. If the 5.2.0 is uninstalled it will uninstall the qt\5.2.0_2 leaving qt\5.2.0 on the disk but not visible in Control Panel installed applications list.