If the application has an uninstaller, please use it and remove the program. You can access it from the Start menu or from the Control panel under Programs and Features or Add/Remove programs.
Once you complete this, please go to Program files and delete everything you find about Pegasus, then use Start > Run > type regedit and press Enter. Expand the Local_Machine > Software, locate Pegasus and delete all the keys. Perform a restart after this operation and Pegasus will be removed from the system.