(Disclaimer: This is a purely made-up word, since such a government system does not and probably will not exist, but because it exists within fiction, I felt it should be noded.)
Government ruled by a computer.
For example, Braniac was the "ruling" computer on Krypton before it blew up. Similarly, the MAGI computers in Neon Genesis Evangelion were basically the rulers of NERV. They made almost all of the decisions when possible.
Clearly the problem with computocracy is that the computers must not only A) have some enhanced AI going on, and B) be free from the bias of the creator(s) of the program. It's highly doubtful that computers would ever replace humans as the decision makers, but it was also doubtful that the world was round...