Well, would be nice to understand how it somehow came to be like dbltoe is asking about. But was there a database modification that went wrong? Configure.php file pointing to the wrong database? Accessed an alternate admin directory? Delete some of the language files? Rename files? Sneezed one too many times?
There are quick fixes, but that's more likely to lead to additional problems down the road, especially if the problem happens again. That quick fix would be to basically reinstall or remove and install. Both plugins support that relatively easily, but if can't identify why it happened then either that or something worse may happen next time..
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