Windows Password Protect Work Around?

Last weekend I had a family visit my country place. Amongst them was a smart alec fourteen year old girl who is pretty sharp with computers. Before their visit I password protected my computer which uses Windows Vista. I went to bed and left my computer room open. The next day I turned on my computer and entered my password. When everything was loaded on the screen I found I had no internet connection. I then spent a lot of time on the phone with my server technician and discovered that the internet connection settings had been disconfigured. I asked him if it was possible that the smart alec (who can´t stand not having access to her Hi5 page for five minutes) had tried to work around the password protection after I went to bed and and in doing so changed the internet settings. He said it was possible but that Windows Vista it´s self is capable of making unwanted changes. So my question is what do you think? Could she have caused the problem by tinkering and trying to bypass the password protection? If so how? Or was it just an amazing coincidence?