Splashtop is composed of 2 software components, Splashtop Personal app and Splashtop Streamer. The Streamer is installed on computers that you want access to. The Personal app is used to remote into those streamer computers. Uninstall steps below:
Open the Splashtop Streamer dmg that you downloaded to install from www.splashtop.com/downloads. There is an uninstall script in the dmg.
From Control Panel, click on "Programs and Features". Then find Splashtop Streamer program to uninstall. You can uninstall the Personal app here as well.
If the install was corrupted, you may need to run the cleanup script to remove/uninstall the Splashtop program. (CleanUpInstallerSRS.zip for streamer and CleanUpInstallerSRC.zip for the Personal app)