Client Version, Can't Login

"Your current client program version is too low. Please exit and update."

What does this mean? I've never seen this before, and the startup page doesn't show any possible updates.

How can I fix this? It won't let me log into my account so I can start playing the game.

A few days ago my computer did have a few issues that my dad tried to fix (therefore causing more problems b:chuckle ). My memory/date time got really messed up xD. He automatically thought I managed to get some bad virus, and in the process added a lot of updates. None of which I would think would cause any problems.