Somewhere I need to switch something off but can't remember where. When I underline a word, the whole document gets underlined, or made bold, or whatever. If I undo a couple of times I get what I want but there's got to be another way! Anyone help please.

See Formatting applied to one paragraph affects entire document by Suzanne S. Barnhill, MVP. I suspect this describes your problem and how to cure it.

Thanks Charles. I've seen this before but couldn't remember where! Now it's sorted.