Does your notebook can access your PC ? Either network share and/or ping ?
You can try to disable your firewall on your PC (temporarly) to see if it fix the problem. If it does you need to make sure all ports needed by Itune are opens. Make sure you reactivate firewall on your PC after the quick test !
This discussion is talking about Xfinity router problem, is this your router ?
Which router are you using ? Also, is your router connected to internet AND provide your Wi-Fi ?
Might be the same kind of problem than with the Xfinity which is also a "router/cable/wifi' combo hardware. Look like internaly "router/cable/wifi" combo hardware put bridge and/or routing rules between LAN and WiFi causing Apple Bonjours packet to be drop.
Bonjour packet are build to be drop after one hop if it pass a bridge and/or router in a network. As an example at home im using a pfSense router (Unix running tailored routage software), with this setup I can't reach my local network itune service if I try to isolate my WiFi in a different VLAN than my local network for security purpose.
So I have been forced to put WiFi router (in my case D-link and also a Airport express) and desactivate all routing functionnality on it to simply act as a WiFi hot spot inside my local network.
So if you are some knowledge in networking, you could try to configure another WiFi devise (Another router with disabled routing functionnality) inside your network making sure to disable DHCP on it and also to put a different IP adresse than the usual (192.168.0.1 or 192.168.1.1) which your Thomson is probably allready using. Ping a free address in range like this 192.168.0.5-9 or 192.168.1.5-9 and fix the WiFi devise to this IP. Then connect your WiFi devise using LAN port to a free LAN port anywhere in your network. Don't use WAN port on your WiFi since your will get in the same problem you experiencing now.
If this work you will know your Thomson router is probably doing some networking trick between WiFi and LAN which cause Bonjour packet to be drop somewhere in the process.