I downloaded a trial versions module from a third-party vendor and uninstalled correctly through the host->module definitions->clicked on pencil->uninstall.   As uninstallation didn't remove code from the file system, I still have files for the control under Desktopmodules, should I just delete the directory for that module.  What about additional files that have been installed to the DotNetNuke installation that for that module? 

Sincerely,
Rodriguez

Yes, you can delete the directory. There is an uninstall option that must be checked to delete files.