I purchased MEP 15 PLUS today and so far it is taking over 3 hours to install. Seems to be stuck on "Copying file: c:\program files (x86)\MAGIX\Common\Database\unwise.ini" "Installation Progres: 98%" for well over 2 hours now. Is this normal? Or is there a problem with the installation?
Check whether the installer is possibly prompting for some kind of entry in the background. Maybe there's some dialog window or OK button hidden behind the main window that needs to be confirmed. You can switch between windows/tasks by pressing ALT+TAB.
Could also be security software messing with your installation process. Consider an installation in Windows safe mode to avoid a good deal of potential trouble and software conflicts.