Usually runtime package is DLL files and support libraries for the main program. These packages are installed on target computers where the user will need to run an application or manage content related to MapInfo. So developers, instead of recommending to install the full application, provide only the support files, usually embedded into these runtime packages.
You will find the runtime entry in the Add/Remove Programs in Control Panel. As you didn't specified I believe it's there. If it's completely missing from that location, I advise you install the package again and then visit Add/Remove Programs and perform the uninstallation.
Please keep in mind that these installers have no impact on your system's performance.