Please add spaces between words: IfyourPCopenstheHD2file,butit'sthewrongapplication,you'llneedtochangeyourWindowsregistryfileassociationsettings.Inotherwords,WindowsisassociatingHD2fileextensionswiththewrongsoftwareprogram.
If your PC opens the HD2 file, but it's the wrong application, you'll need to change your Windows registry file association settings. In other words, Windows is associating HD2 file extensions with the wrong software program.