Hmmmmmmmm did you leave your comp on the internet without a firewall ........... because I remember recently hacking someone who left there comp online and doing exactly that. Didnt your Dad ever give you a lesson on protection.

OK on a serious note if you dont have a firewall hackers do simple things like that to being very ferocious and I highly reccomend getting a firewal if you don't your comp is very vulnerable. As far as changing it back I have no idea.