have the right think
open the commandbox, change directory to xampp path
type " apache_start.bat "
and now you start within the apache manuely and now you see any text, if there any error message ?
if not and you cant see anything unter httpd://localhost
, i think then you have turn on the internal Firewall of winXP-SP2.
check this, turn off or change firewall-rules to open port 80