I would like to Block users from Downloading and installing Firefox.?

I would like to Block users from Downloading and installing Firefox. Users also ran firefox off USB drives so I had to disable USB jump drives. Is there a way to block Firefox using the Windows Firewall or can this be done with a Cisco Firewall? I have also tested Group Policy and Setup only run certain process however that doesn't work that well seeing as someone could rename the firefox.exe... Any help or suggestions would be greatly appreciated...