Actually i just want to know how i can change mysitename/?board=22.0 this url to mysitename/boardname
thank you :)
There is one MOD called PrettyURLs that shows the URL from actions, boards and threads as you say, the name of the board, thread or action, but it have some issues with certain MODs and if you change the name of one board, the URL don't get updated easily, and if you have other things in a subdirectory of your forum it will not work well as it will think that it is a board or thread and will redirect you to the front page.
The biggest question is, why do you want to do this?
If you think that it matters for seo, or google... it dies not.
Also, it looks like you have already done something to remove the ndex.php from yoyr url... that is a bad udea, overall and would have to be undobe before applying prettyurls.