There is presently an outage with HOTMAIL, so many have problem accessing their accounts.
You mention you little brother can access these sites; then you must be on a network. In some cases if one PC is using a specific application, the other may have problem. Have you tried closing the other internet connection(s) so that you are alone and have all the bandwidth. What type of connection do you have? So you have service pack 2 installed? Did you check your firewall settings. Do a line test at this address to check if your connection is OK