I was able to disable
file download popup in all popular browsers except Internet Explorer.
This is the popup:
I thought this would do it, but I still get the popup:
Internet Explorer > Tools > Internet Options > Security > select zone (example: Internet) > Security levels for this zone > Custom level... > Downloads > File download > Automatic prompting for file downloads > Disable > OK > Yes > OK.
I am not interested in automating the popup, I do not want it to appear.
OS is Windows 2003, Internet Explorer 8.