Thanks so much, I deleted the file my setup and everything is working again. I am not sure what I clicked to make it happen in the first place, but a couple of minutes earlier the chord chart turned into a strange symbol thing with ~ over the letters and when I closed it it created an identically titled song but with the .MGU ending.
Still thanks for the prompt response, its a steep learning curve and it feels reassuring to know knowledgeable help is at hand.
Cheers Steve