I opened a new blank document of Word and then tried to open one of my files
using the open icon on the toolbar and accidentally clicked on the save icon
instead. I did not realise this however and carried on to search for my file
and when i found it i clicked on it and only then realised that i had
actually saved the blank document over the top of the text file that i had
been trying to find.

Does anyone have any idea how to revert back to a previously saved version
of a document?