Can't turn the wifi thingy on the laptop on now.
The button is not functioning and I cannot find another way to turn it on.
I managed to uninstall AVG and can turn off Windows Firewall, but now cannot test BM's suggestion.
Have a look to see if it is disabled in Device Manager
Also check the craptop for wifi on/off switches which you may have moved while fiddling round with ethernet cables.
Also, some craptops (like my Tosh) have button combinatios to turn off wifi in the soft side - Ctrl-F4 I seem to recall. The two together (soft and hard switches) give you three to one against it working - try all combinations.
Good luck!