PS - forgot to add - from your PC . when you do an 'ipconfig/all' entry in the CMD Command screen, do you see Primary and Secondary DNS Servers which are identical to the DNS servers in the Sagemcom Modem?
I used a different dongle (Belkin) and found out it only support Windows 7 so I thought it could be the problem. I bought a new one from Officeworks that supports Windows 10 and installed the driver. The result was just the same with my old dongle. Yes I removed the connection from Optus router and redo everything like scanning it freshly, put the SSID again and password but to no good.
I was planning to disable first the TrendMicro antivirus or probalbly unintall it for the meantime then re-install later. I highly suspected it could be the one blocking my internet access.
I'm using Firefox by the way.
Sorry I am little confuse with where it the connection fails over.
Optus modem -> wifi -> dongle ->PC
You said reinstall the dongle and scan the SSID and not working, is that means you can't connect to the wifi network at all? But at ealier post you said that you can see the Optus Modem webpage?
1. Is your internet working? Can you connect to the internet with your phone to the Optus modem?
2. Can your dongle connect to the Optus modem? Maybe try different USB port.
3. Can the PC connect to the internet.
My suggestion is connect your PC to the modem via a network cable and let all the windows update and instalation to complete. See if you can get a internet connection. Remove the dongle and uninstall all the wifi associated drivers and programs. Download the lastest program from the dongle on while you are connected. Reboot and install the new program and driver. Connect back the dongle and see if it is working. Try to connect to the Optus modem. If failed, turn on Hotpot or Teethering on your mobile and see if the dongle can connect and have an internet connection.