try to look in your style.css if there is something like:

p {font-weight:bold;.........}

and delete it

I love this theme but I have a problem when I write a news. The text is all in bold.

I see a lot of <p> and when I delete those, the text is then normal.

Which file do I have to edit to take off bold? I looked in css file but I can't make out where I should look.

Thanks for your help.