I was given the solution to the tethering problem, and here it is!
1. Go to Settings, Connections and click on Connections Icon
2. Click on "Manage existing connections"
3. Click on Edit... for the Bell Mobility connection
4. Click Next, Next and then Advanced button
5. Go to the "Servers" tab
6. Change this option : put it to "Use server-assigned addresses"
(You can note on a paper your DNS and Alt DNS numbers in case, cause it will be deleted after).
7. click ok. Click Finish.
8. Try to connect.
9. Surf the Internet !!!