I have found my problem..
Installshield can be easily uninstalled but the problem was coming from proxy settings of Windows 10.At the beginning I couldn't set the proxy settings in "Control Panel" due to an administrative right.
I have changed "Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Control Panel "Connection Settings" 1--->0 then changed in IE Connection Settings/LAN Settings "Automatic Detect Settings"
View attachment 142384
Now it's OK, Installshield has gone and Internet connection is OK>