Guys
Thanks for all the advice. I have now (with the help of the shop) worked out what the problem is - I will advise below in case anyone else gets the same problem.
It appears that a photo file (1 of about 2000) is corrupt

. This is stored in the 'My Pictures' and it appears that Word etc always looks there first. Once this corrupt file has been accessed (as MS always does when it looks in a directory - it will corrupt the application - even if the file is not loaded itself, or you go someone else to get a file.
All I now need to do is check whcih file it is!
Thanks again for the advise.