Can't join Minecraft server (friend)?

If my friend wants to join a Minecraft server, it says the login servers are currently down for maintenance. We're sure he's down to his laptop. When we wanted to reset his laptop, it said that we need a CD or a USB stick, which of course we don't have. Are there any other ways to solve this problem? (we have already tried to restart Minecraft several times)

Have you rented an external server or do you use a peer-to-peer connection?

It doesn't work with all servers, so it can't be on any server, we don't have our own either

You can turn off your firewall as a test and try again. Check internet connection, something might not work there.