I am at my wit's end! I didn't realise that DropBox would corrupt files. I now have several Word documents in a folder that I need for my course work assessment which are no longer Word documents and which won't open. I'm actually really worried - I trusted DropBox and am actually thinking I shouldn't have...Can anyone tell me what has happened please?

Also my tutor is unable to open the PDF files - they open with a padlock and are so tiny he can't read them...he is one of those listed as being able to open them (TM ).
Please help me - I need all this for my assessment and am now seriously worried.
Thank you.