try checking apache's error.log to see what the error is, post the last error here if you don't understand how to fix it yourself. otherwise we can't help
When Apache refuses to restart the server is because you made a typo while editing your httpd.conf file. Double check if there is not a missing comma, semi-color or non-existing path before retry.
you did made a backup of httpd.conf before editing, right? if not.. check the lines you have edited, there is probably something there that is messing it up. Also, check error_log as suggested, and other logs also, depending on which server/configration you are running (/var/log/messages etc.).
From one peon to another: Try emacs: it automatically makes a backup of your files. That way, when you have a stray ^C or whatnot you can just copy the backup to the one apache looks for. It has saved me so, so many times. Scott
it's will be more better for checking error_log because it will give you more specific error message why your apache can't running well