That it shows up as an "Interlink Elite" in the device manager is a good sign.... however it should calibrate just fine... assuming for the moment that it is ok however...
Since you've uninstalled the software, reboot and log back in.
Start by looking for any vestiges of the software in the hidden "Application Data" folders and delete those.
You could also delete any registry entries, but this may not be nessary.
After you've deleted the hidden files, right click on the SETUP program located on the DVD and select "run as administrator".
Let the installation run until completion. Make sure you accept the DirectX9.0 install too.
Once done, right click on the launcher and again "run as administrator". You may or may not have to re-enter the serial numbers...
Bring up Realflight ( you still should be in the launcher as administrator ) and see if the Interlink is recognized. If so calibrate and exit.
Once done run the launcher as a normal user.