Bizarre MS Word Problem

I've got a slightly bizarre problem with MS Word. Quite often at university, I'll be typing a document and my left and right cursor keys will be reversed. This has now happened with a document on my home PC that I've edited at university - I've also noticed that left and right align are reversed, and that the ruler along the top of the page runs right to left rather than left to right. I suspect this is something to do with being configured for some strange language that runs backwards, but can't find anything. Anyone know?

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