start IE even if you dont use it click Tools>Internet Option>Connections Tab>Lan Settings>uncheck "Use a proxy server for your Lan(these settings will not apply to dial-up or VPN connections). ... refresh page to se if it works
you probly had av security suit virus (had it 2 times this month) i can give you a link to a guide and downloads to take care of it if you need or just incase you get it again just pm me if you want them