Hi, AngelikLark! I'm not sure if you've fixed this up yet, so I'll see if I can help.

Judging by your signup/last active dates on your forum profile, if those are in fact correct, your problem is likely what Septina suggests - Minecraft version 1.7.9 is the only release currently compatible with the server.

Using the vanilla launcher, you'll need to either create a new profile or edit your existing one before logging in to the game and tell the launcher to specifically use 1.7.9, more than likely via the "use latest version" option. Once you've done that, you should see a note somewhere on the launcher that 1.7.9 will be installed, and when you click to play and load the game that should be taken care of. You should then be able to access the server as you could before.

Just in case you somehow do in fact have the wrong IP, you can go ahead and cross check our current one with the one you have entered, like Exo suggested as well. You can simply select the Creeper's Lab on your multiplayer server list and click the "edit" button. The current server address is 192.210.229.66:25565

Let us know if neither of these work out to solve your problem, and we'll see what we can do. Also remember we have the IRC chat connected to the players in-game, which you can find the link to via the "Chat" link on the right sidebar of http://www.creeperslab.net , so someone online might be able to lend you a hand there as well. Good luck!!

I see you've found your way on the server since your last post. Good! Let us know if something else is wrong!