I'm new to XAMPP/Apache and have just installed them on a Vista Home Premium based computer. Apache would not start and I kept getting the 'busy' on port 80 message. Apache would start when I changed the LISTEN port address in 'apache\conf\httpd.conf'. But I wanted to understand what was blocking apaches access to port 80. So....I uninstalled Skype and IIS7 but the problem persisted. Telnet and Netstat programs failed to identify the 'culprit'. Finally, this morning I came across a posting which stated SQL Express reporting services uses port 80. Sure enough, when I disabled this service then apached started. This is but one more tidbit of information that newbies should consider.