If you say that you want to launch desktop with Browser/HTML, you should not be asked you if you have View client already installed. However the other message that you say is coming from browser and is reasonable.
What is the Browser version that you are using. Is it I.E.8.0? If so,
Change the security level setting in Internet Explorer to Display Mixed Content.
Open Internet Explorer>Tools > Internet Options>Security tab> Custom level>Enable for Display Mixed Content.
Restart browser and check if it works.