Открываем файл, который, как и предыдущий находится в корне сайта. Находим строчки в самом начале:

DirectoryIndex index.php
RewriteEngine On

Вместо них вставляем:

RewriteEngine On
Options +Indexes
Options +FollowSymLinks

# Редирект для категорий (чтобы в конце URL был /)
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !-f
RewriteCond %{REQUEST_URI} !/$
RewriteCond %{REQUEST_URI} !.html$
RewriteCond %{REQUEST_URI} !.xml$
RewriteRule (.+) $1/ [R=301,L]

# Редирект c www на без www
RewriteCond %{HTTP_HOST} ^www.site.ru
RewriteRule ^(.*)$ http://site.ru/$1 [R=permanent,L]

# Редирект для главной (с /index.php,html на /)
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9} /index.html HTTP/
RewriteRule ^index.html$ / [R=301,L]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9} /index.php HTTP/
RewriteRule ^index.php$ / [R=301,L]

DirectoryIndex index.php

RewriteEngine On

# Редиректы
RewriteRule ^page/(.*)$ index.php?cstart=$1 [L]

# Сам пост
RewriteRule ^([0-9]{4})/([0-9]{2})/([0-9]{2})/page,([0-9]+),([0-9]+),(.*).html(/?)+$ index.php?subaction=showfull&year=$1&month=$2&day=$3&news_page=$4&cstart=$5&news

_name=$6 [L]
RewriteRule ^([0-9]{4})/([0-9]{2})/([0-9]{2})/page,([0-9]+),(.*).html(/?)+$ index.php?subaction=showfull&year=$1&month=$2&day=$3&news_page=$4&news_name=$5 [L]
RewriteRule ^([0-9]{4})/([0-9]{2})/([0-9]{2})/print:page,([0-9]+),(.*).html(/?)+$ engine/print.php?subaction=showfull&year=$1&month=$2&day=$3&news_page=$4&news_na

me=$5 [L]
RewriteRule ^([0-9]{4})/([0-9]{2})/([0-9]{2})/(.*).html(/?)+$ index.php?subaction=showfull&year=$1&month=$2&day=$3&news_name=$4 [L]

RewriteRule ^([^.]+)/page,([0-9]+),([0-9]+),([0-9]+)-(.*).html(/?)+$ index.php?newsid=$4&news_page=$2&cstart=$3&seourl=$5&seocat=$1 [L]
RewriteRule ^([^.]+)/page,([0-9]+),([0-9]+)-(.*).html(/?)+$ index.php?newsid=$3&news_page=$2&seourl=$4&seocat=$1 [L]
RewriteRule ^([^.]+)/print:page,([0-9]+),([0-9]+)-(.*).html(/?)+$ engine/print.php?news_page=$2&newsid=$3&seourl=$4&seocat=$1 [L]
RewriteRule ^([^.]+)/([0-9]+)-(.*).html(/?)+$ index.php?newsid=$2&seourl=$3&seocat=$1 [L]

RewriteRule ^page,([0-9]+),([0-9]+),([0-9]+)-(.*).html(/?)+$ index.php?newsid=$3&news_page=$1&cstart=$2&seourl=$4 [L]
RewriteRule ^page,([0-9]+),([0-9]+)-(.*).html(/?)+$ index.php?newsid=$2&news_page=$1&seourl=$3 [L]
RewriteRule ^print:page,([0-9]+),([0-9]+)-(.*).html(/?)+$ engine/print.php?news_page=$1&newsid=$2&seourl=$3 [L]
RewriteRule ^([0-9]+)-(.*).html(/?)+$ index.php?newsid=$1&seourl=$2 [L]

# За день
RewriteRule ^([0-9]{4})/([0-9]{2})/([0-9]{2})(/?)+$ index.php?year=$1&month=$2&day=$3 [L]
RewriteRule ^([0-9]{4})/([0-9]{2})/([0-9]{2})/page/([0-9]+)(/?)+$ index.php?year=$1&month=$2&day=$3&cstart=$4 [L]
# За весь месяц
RewriteRule ^([0-9]{4})/([0-9]{2})(/?)+$ index.php?year=$1&month=$2 [L]
RewriteRule ^([0-9]{4})/([0-9]{2})/page/([0-9]+)(/?)+$ index.php?year=$1&month=$2&cstart=$3 [L]
# Вывод за весь год
RewriteRule ^([0-9]{4})(/?)+$ index.php?year=$1 [L]
RewriteRule ^([0-9]{4})/page/([0-9]+)(/?)+$ index.php?year=$1&cstart=$2 [L]
# вывод отдельному тегу
RewriteRule ^tags/([^/]*)(/?)+$ index.php?do=tags&tag=$1 [L]
RewriteRule ^tags/([^/]*)/page/([0-9]+)(/?)+$ index.php?do=tags&tag=$1&cstart=$2 [L]
# поиск по доп полям
RewriteRule ^xfsearch/([^/]*)(/?)+$ index.php?do=xfsearch&xf=$1 [L]
RewriteRule ^xfsearch/([^/]*)/page/([0-9]+)(/?)+$ index.php?do=xfsearch&xf=$1&cstart=$2 [L]
# вывод для отдельного юзера
RewriteRule ^user/([^/]*)/rss.xml$ engine/rss.php?subaction=allnews&user=$1 [L]
RewriteRule ^user/([^/]*)(/?)+$ index.php?subaction=userinfo&user=$1 [L]
RewriteRule ^user/([^/]*)/page/([0-9]+)(/?)+$ index.php?subaction=userinfo&user=$1&cstart=$2 [L]
RewriteRule ^user/([^/]*)/news(/?)+$ index.php?subaction=allnews&user=$1 [L]
RewriteRule ^user/([^/]*)/news/page/([0-9]+)(/?)+$ index.php?subaction=allnews&user=$1&cstart=$2 [L]
RewriteRule ^user/([^/]*)/news/rss.xml(/?)+$ engine/rss.php?subaction=allnews&user=$1 [L]
# вывод всех последних новостей
RewriteRule ^lastnews/(/?)+$ index.php?do=lastnews [L]
RewriteRule ^lastnews/page/([0-9]+)(/?)+$ index.php?do=lastnews&cstart=$1 [L]
# вывод в виде каталога
RewriteRule ^catalog/([^/]*)/rss.xml$ engine/rss.php?catalog=$1 [L]
RewriteRule ^catalog/([^/]*)(/?)+$ index.php?catalog=$1 [L]
RewriteRule ^catalog/([^/]*)/page/([0-9]+)(/?)+$ index.php?catalog=$1&cstart=$2 [L]
# вывод в виде каталога
RewriteRule ^cat/([^/]*)(/?)+$ index.php?catalog=$1&n=1 [L]
RewriteRule ^cat/([^/]*)/page/([0-9]+)(/?)+$ index.php?catalog=$1&cstart=$2&n=1 [L]
# вывод в виде каталога
RewriteRule ^cat/([^/]*)(/?)+$ index.php?catalog=$1&n=1 [L]
RewriteRule ^cat/([^/]*)/page/([0-9]+)(/?)+$ index.php?catalog=$1&cstart=$2&n=1 [L]
# вывод непрочитанных статей
RewriteRule ^newposts(/?)+$ index.php?subaction=newposts [L]
RewriteRule ^newposts/page/([0-9]+)(/?)+$ index.php?subaction=newposts&cstart=$1 [L]
# вывод избранных статей
RewriteRule ^favorites(/?)+$ index.php?do=favorites [L]
RewriteRule ^favorites/page/([0-9]+)(/?)+$ index.php?do=favorites&cstart=$1 [L]

RewriteRule ^rules.html$ index.php?do=rules [L]
RewriteRule ^statistics.html$ index.php?do=stats [L]
RewriteRule ^addnews.html$ index.php?do=addnews [L]
RewriteRule ^rss.xml$ engine/rss.php [L]
RewriteRule ^sitemap.xml$ uploads/sitemap.xml [L]

RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^.]+)/page/([0-9]+)(/?)+$ index.php?do=cat&category=$1&cstart=$2 [L]
RewriteRule ^([^.]+)/?$ index.php?do=cat&category=$1 [L]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^.]+)/rss.xml$ engine/rss.php?do=cat&category=$1 [L]
RewriteRule ^page,([0-9]+),([^/]+).html$ index.php?do=static&page=$2&news_page=$1 [L]
RewriteRule ^print:([^/]+).html$ engine/print.php?do=static&page=$1 [L]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+).html$ index.php?do=static&page=$1 [L]