I fixed my problem by editing the xampp apache httpd.conf file to have the correct port for apache (not conflicting with my IIS7 or RubyonRails port configuration).
To help you with this here is a link to a webpage briefly explaining how to edit the httpd.conf file:http://blog.wolffmyren.com/2008/07/30/making-xampp-apache-work-with-iis-on-windows-xpvista/
Here is the brief outline instruction from that webpage:
Search for “Listen 80″, change to “Listen 8080″
Search for “ServerName localhost:80″, change to “ServerName localhost:8080″
Search for “Listen 443″, change to “Listen 4499″
Search for “<VirtualHost _default_:443>”, change to “<VirtualHost _default_:4499>”
Search for “ServerName localhost:443″, change to “ServerName localhost:4499″
Then, you should be able to start Apache successfully through the XAMPP control panel.
So I advise you know what port you need your xampp apache localhost to run on & make sure you have no other port conflicts on your computer (including Skype) and edit your xampp apache httpd.conf to the port setting you need. OK?
(If you use Tomcat addon see my other post!). I hope this helps & you get your xampp apache server working again. Goodluck (do let us know if you succeed),regards