The PC now having the ability to "see" the other machines on your network, pretty much rules out the Windows as the
source of your problem of no browser connection. The lack of internet could now be either router's hardware or some
security setting for the lan port the PC is hooked to.
I would test the router's ethernet ports, by using the laptop
( Make sure you use the same ethernet cable to do the testing )
Plug that cable into all the ports of the router and make sure that this "proven"
machine (laptop) will successfully gain access to the web through all of the ports.