You should run a test..
Put her laptop on and connect to the net, then go and turn yours on. If you cannot connect at all then the laptop is the problem, logicaly. If you can connect after her's is set up and running it would suggest something in the start up of the laptop maybe. If having her laptop on only causes occasionaly discos than it is probably virus or spyware. Other than that i have no idea, i prefer outside activities and only use my PC for games and pr0.....ductive persuits.