So you're playing Pokemon Black/White and you try and visit your PC box, only to encounter...
the Blue Error Screen! (duh duh duh *dramatic reverb*)
What causes the Blue Error Screen?
The blue error screen is the result of the game encountering data that has somehow been corrupted. This corrupted data can't be read and causes the game to crash. There could be several different culprits, but the one I've seen most often (and the focus of this guide) is incorrect or improperly used AR codes