Hello, ashfaq;
What you mean install mod relate to this ?
after trying to browse your site, it appears that your links work well, each category's link leading to the correct category.
But, when viewing the desired category, the category name shown on the top is not the real one, and changes if you refresh the page.
I noticed you used some MOD to have a Search Engine Optimization (with cat2.htm and not categories.php...blahblah). What other MOD have you applied, please?
Maybe some of your own changes have affected the way to display the category's name.
I think that was Mr. Thunderstrike's question meaning.