Thank you for the quick reply.
I have disabled the Bluetooth, as you suggested.
I also restarted the modem, router and computer as you wrote.
I'm not sure I understand what you mean by
Put everything like it should be...
wall > isp modem/router > wireless router(if any) > wired/wireless
Modem: Arris TM602A
Wireless Router: TP-LINK TL-WR641G
Nothing has changed yet, still getting no internet connection.
Just to clarify - I get a connection only when I connect the computer directly to the Arris modem via Ethernet.