Highwayman is correct, you may be the victim of some bandwidth throttling policy in place by the network admins for the school. Check with somebody else in the dorm and see if they are experiencing the same issues, I would think that if they are restricting bandwidth use that you would probably experience some very poor performance, before you lost the connection completely, also I'm not sure that a system restart would fix the problem since the restrictions are probably applied based on an ipaddress, or mac address, but could be more sophisticated based on applications or application port use. So check with the network admins.
You could also try the basic stuff, like disabling IPv6 in the properties of your network adapter...