ive tried that nothing happens i went to tools and clicked firefox no changes i can go back to tools and look again and nothing has a check by it.
Click Help: About K-Meleon.
What K-Meleon is showing/sending as UserAgentString to a web page is indicated below the moving credits field.
Is when I set it to Firefox: Windows; U; Windows NT 5.1; de; rv:18.104.22.168) Gecko/20081217 Firefox/22.214.171.124 since I use a German K-Meleon version.
For pages that do not like Firefox 2 You can set a custom string.
For some pages it is better to use K-Meleon1.6.beta, which must be installed into a folder with a custom name and the can use the same profile as 1.5.4.
But do a backup before You do such things.