hi, on one of my sites im going to add a front page, its just a Microsoft made front page. in order to not lose traffic i will be only changing index.php to forum.php. actually i just have 3 questions if thats ok!
1.my site stilll should keep its ranking using a front page with the same title and key words etc???

2.changing index.php to forum.php is pretty safe right, like for my forum???

3.its a teen site im messing with, if i change index.php to teenforum.php can that help my forum under the search term teen forum???

4.or should i just make a sub domain for my forum?? im just worried i'll lose whats been indexed by google.
but my domain url should keep its place on google right??? even if i make a sub forum.

teenforum.php
or
teenforum.mydomain.com

thanks.