Wifi suddenly stopped working, but works with Ethernet, iPhone/iPad still works???

what did they do with the DNS issue ?
hence the request for ipconfig /all
can we see that from the windows PC
did they setup up an open DNS in the router or on the PC

With the PC working on cable - can we see an ipconfig /all
and then just with wireless another ipconfig /all - make sure we know which is which, this may help with the DNS settings

on a MAC if

ifconfig

in Terminal type "cat /etc/resolv.conf"; the IP addresses of your DNS servers should be listed there.

if you set the router up to use google open dns
8.8.8.8
and
8.8.4.4
and then set the PC to automatic that should work

or to find the best DNS to use in your country (usually the ISP DNS are good enough)
here is a tool

I have found these to be a useful tools to use for DNS testing
https://www.grc.com/dns/benchmark.htm
https://code.google.com/p/namebench/

Google public DNS
Note using google public DNS servers from outside the US may actually slow performace - so use the following as a test to identify DNS issues - if these resolve the issues , then we need to investigate further to optimise the use of DNS


Google public DNS
https://developers.google.com/speed/public-dns/

Theres also a link on how to setup those DNS IP address up on a PC
http://code.google.com/speed/public-dns/docs/using.html

Then once you have set up those DNS entries

Flush & register DNS

Hold the Windows key and press R, then type CMD then press Enter to open a command prompt box (A new dialogue box - black with white font, will appear on screen ):
In the command prompt window that opens, type the following commands:

Ipconfig/flushdns
ipconfig/registerdns

If you receive the message
The requested operation requires elevation.
Then please open the command prompt as administrator
Start> All Programs> Accessories and then right click on Command Prompt, select "Run as Administrator" to open a command prompt.

now type the command again