Check your system tray for eaytune6 Icon
Easytune6 is a little tricky. When you click on The program (shortcut on desktop) it normally does not open but installs in the system tray (Right hand side). And you then have to click on the icon in the system tray.
For Re-installing/upgrading
.. as stated if installed, try uninstalling from control panel, remove program. Reboot, then run a registry cleaner such as CCleaner. Then try re-installing.