Keyboard insanity, please help!

[erik]

Somehow I hit a key that causes my type to erase going forward when I correct a mistake thereby making it necessary to retype the entire post. You can't enter a space without erasing the following letter. Why does this happen? Who thought this would be a great idea? How can I reverse it when it happens without having to restart my computer?

[Jack Stoner]

It's the "Insert" Key. It's a dual function key. It it's overtyping instead of just inserting, press the key and it will change operation.

[erik]

Thanks much, Jack.