Ah, I see.
A few checks:
from the very bottom of your machine, right hand corner do you see the xampp icon, if not it might be within the hidden icons, if it's not there go to start, programs and start xampp
If xampp is started then "restart all services" Are they restarting OK?
do you connect to a database, did you import your db using phpMyAdmin?

Next: open your browser and type http://localhost/ report what you see.
is your site loaded within www/ and is the index a .php?

last go to windows/system32/drivers/etc/hosts
open host with your fav editor or notepad if notepad be sure to turn on the "all files"
do you see:
127.0.0.1 localhost ?
if your site index is not directly at root (www) but is in a dir/
like my_site/index.php
then add to your hosts file the following:
127.0.0.1 my_site
save and go back to browser and try it again.

out of curiosity to check if Apache really runs
create a file
<?php
phpinfo();
?>
rename the default root index as index_OLD.php
save the new file as index.php
go back to localhost it should give you all the php.ini setting
if not I will uninstal it and try wamp server or wamp five which are very solid!

let us know