cant change sketch - i get computer 'ding' with each key press

While trying to simply change the time in between blinks in the basic example "blink" , my computer will not let me change anything in the sketch , and gives me a loud "ding" error. It must be something simple. Any ideas ?

What error you are getting . Please share us screen shot.

it is not an on screen error , but an audible bell ring

Go to the IDE settings and deselect "use external editor"

Perhaps it won't let you make changes in a read-only sketch. Try using "File->Save As..." to save the Blink sketch in your Sketchbook folder. Then you should be able to edit it.

Thank you very much , it was indeed the external editor that I had checked. I appreciate your help.