Any chance you have an IP address conflict? Maybe something you have has a static address that was OK in the old setup, but that conflicts with the new router's DHCP scheme or even the routers address?
Definately check with a wire to eliminate radio issues.
Try setting the DNS server to one of the public ones. Easy in windows, no idea about linux.
8.8.8.8 - google
9.9.9.9 - someone else
OpenDNS
Did you bring your old router too? More than one DHCP server would be bad news.