DSL box and routers do not connect to the Internet

Hello!
I need some help with my Internet. I have a DSL box and a router but then my computer would not connect to the Internet. I tried diagnosing the problem and it was suggesting that the trouble could be caused by the firewalls.
I tried turning them off but it still wouldn’t work.
Can you tell me what could be wrong with my computer?
I would appreciate any kind of help.
Looking forward to your valuable replies.
Thank you.
Weigelt
