I'm having trouble connecting to the internet. Experts, please help me?

I can connect to LAN, but not the intenet. I have Ethernet cable, but not WiFi. Is this a possible cable problem, Router problem, or motherboard/adapter problem?

I have followed every single troubleshooting guide and ran Win10 troubleshooter
Update: this was during and shortly after reinstalling Win10.

this was also shorty after I switched from ADSL to Fibre. I know the internet works fine, because out of the 5 people using the internet in my house(all of them have a similar network setup to me, I'm the only one who's experiencing trouble.
Update 2: Edit 2: I am running a custom built (albeit old) PC
5 answers 5