I want to remove the rounded corners on the new Atahualpa 3.5.3 Wordpress 3.0.1

I am really confused as the older themes' menu system was fine for what I wanted. If someone can help buy explaining how to have my menus the same as they used to be I would be grateful

Thank you

go check out what you have in your css inserts.

Yep I take it that is in the theme options............... Thank you