SystemDoctor, also known as System Doctor, is a corrupt program that purportedly repairs damaged files, fixes registry problems, prevents data losses, erases Internet tracks etc. However, it is actually a poor performance application that produces incorrect, exaggerated system check results. SystemDoctor’s main purpose is to trick the user into purchasing its paid version. The program displays commercial advertisements and opens annoying pop-ups. It may also secretly download from the Internet and install other threats. SystemDoctor runs on every Windows startup. The application is illegally installed to user computers by widely spread parasites, through drive-by downloads, and via numerous exploits.