@aburka as someone else already mentioned, the live CD/DVD/ISO might show different wifi driver than the final install. Had this once with Linux Mint on my dad's 2009 iMac. Fortunately his neighbour had a long enough ethernet cable to go directly into the router to download the correct drivers. Since then I added the cable to my mobile toolbox. But as a linux newbie it took me some time to find out and solve this.