A child I tutor was typing in Google Docs on a Dell laptop yesterday. Then suddenly, after he [View all]

backspaced to delete a mistaken letter, any further attempt to type a letter resulted in a previous letter being replaced by the new letter. For example, when he tried to add "d" to "awar" to get "award," the " d" instead replaced the "r," producing " awad." We couldn't figure out why it happened or a way to make that stop. We even exited and then returned to Google Docs and, when that didn't work, we rebooted the computer. That didn't help either. Now he can't use that computer at all for his project (he is required to us Google Docs for the project).

I am guessing he must have used the wrong key to delete something, but I don't know which key that would be, or which key to use to make it go back to normal. Also, of course, we need to know which key caused the problem so it won't happen again.

I use a Mac, and I don't use Google Docs, so I am at a loss.