Stupid Backspace Problem!

Word is behaving strangely

[CeliaMM]

Not sure if I'm posting this in the right place, but hopefully someone out there will shed some light for me.

Not too long ago I was putting together a document in MS word and my backspace button stopped working when highlighting sections to delete. I'm not blaming Mr backspace completely though, because when I highlight a sentence or set of text and try to write something in its place, it doesn't work either. The text simply appears next to the old.

I realise this might be some ridiculously small error I've missed, but please, anyone got any clue whats going on?

Sorry this is a bit like a Computers For Idiots posting.

[jessejump]

Tools / Options / Edit >>>> Typing replaces selection

[mattglet]

Make sure the Insert key on the keyboard is working the way you want to.