I am not sure what you mean, please can you elaborate by answering these few questions:-
1. What make/model of router does your daughter have (if this is a TalkTalk router, these details will be on a label on the rear or underside of it)?
2. What is the exact status of the lights on the front of the router when this happens?
3. If you have any wired connections, are they affected in the same way as wireless ones?
4. Can she actually connect to the router's Wi-Fi, but can't get out to the internet?
5. Are there any error messages & if so, exactly what are they?
