Uninstall Citrix Receiver
From your local computer (outside of the Citrix desktop) after you have logged off/signed out from Citrix.
Click on Start and type/search for Control Panel.
In Control Panel under Programs select Uninstall a program
Select Citrix Receiver/Workspace on the list and click Uninstall towards the top of the list.
Click Yes when prompted if You Are Sure You Want to Uninstall
The Program will uninstall and will be removed from the list.
You should reboot your computer before trying to install the application again