Top catigory selection

https://scourcetalk.awardspace.com

What can I change, so the selected page in the top nav bar is based on the category of the post??

If you look at my site, I have a cat called Linux and a Page called Linux, so I want top nav Linux to be selected when the user is in a Linux cat post.

I found the code:
<ul class=”menu”>
<?php if (‘page’ != get_option(‘show_on_front’)) { ?>
<li class=”<?php if ( is_home() or is_archive() or is_single() or is_paged() or is_search() or (function_exists(‘is_tag’) and is_tag()) ) { ?>current_page_item<?php } else { ?>page_item<?php } ?>”>/” title=”<?php echo get_option(‘k2blogornoblog’); ?>”><?php echo get_option(‘k2blogornoblog’); ?>
<?php } ?>
<?php wp_list_pages(‘sort_column=menu_order&depth=1&title_li=’); ?>
<?php wp_register(‘<li class=”admintab”>’,”); ?>