My Windows Media Player has suddenly started to play some video files
upside-down, but they played perfectly okay before.

It doesn't appear to affect any particular type of file but one is a 'wmv'
and the another is an 'avi' - however, the other 'wmv' and 'avi' files are
okay.

Though I've tried, I can find no way of correcting the problem, so, I'd be
grateful for any help.

John