First things first;
A Now TV box provides
additional channels (and catch-up facilities) to whatever a TV set can already receive but it doesn't provide access to normal Freeview channels. So, once your friend has got the box working (with a TV set that hasn't got an aerial connected to it), she'll be able to view Gold, Sky 1, Sky Atlantic and all of the other Now TV channels (plus BBC iPlayer, ITV Player, YouTube, etc) but she won't get live transmissions from BBC One, BBC Two, ITV, Yesterday,Dave, etc.
Next, can we assume that your friend has actually got a router broadcasting a visible wifi network? (Use a laptop or mobile phone to check that you can see it).
Can we also assume that the Now TV box has got a power supply plugged into it?
Then can you tell us what, if anything, your friend sees when the TV set is switched to the HDMI input? Has she tried pressing the buttons on the remote control (for the box, not for the TV) to see if anything comes up?
Has she tried the Now TV Live Chat help system? It's almost impossible to find on their website but this link should take you to it:
http://tinyurl.com/zqdhtz4