[Lawrie]

UPDATE to the above, I have now experienced the same problem daniel was referring to.  I went into the display settings to see if I could replicate his problem by turning on full screen  mode and experimenting with hiding the navigation bar.  I was able to then replicate daniels problem.

I ended up having to exit MS altogether and restarting it to restore functionality.  

What I noticed though, while the problem persisted, was that the text didn't go to white on white, but some very pale colour on white.  Still impossible to actually see, but it was there, if just barely.