Random running on the time-line!

I have successfully made many MM videos in recent years - no problem.  Out of the blue I now have a problem, and 'un-installing' and re-installing has not solved it!    

When importing photos onto the time line it does not play them in order, and when I place the cursor at a point it displays a photo that is some way back!  Cross fading between photos just fades to the 'wrong' photo in an almost random manner.

Even perfect projects from the past now seem to play in this mischievous manner.

Any ideas on the resolution would be appreciated,  (Windows 7 and MM v2012)

<Original title - Timj Smith  >