Newbie: Error loading localhost

[Sher99]

When loading XAMPP I get several errors.
Apache will start without error after pressing the <Start> button, but pressing <Admin> tries to load the localhost and I get error:

HTTP Error 404. The requested resource is not found.

How can I correct these errors? THX

XAMPP Errors:

1:55:07 PM [main] You are not running with administrator rights! This will work for
1:55:07 PM [main] most application stuff but whenever you do something with services
1:55:07 PM [main] there will be a security dialogue or things will break! So think
1:55:07 PM [main] about running this application with administrator rights!

I already changed httpd.conf to "Listen 8080" instead of "Listen 80":

2:20:03 PM [Apache] Problem detected!
2:20:03 PM [Apache] Port 80 in use by "Unable to open process" with PID 4!
2:20:03 PM [Apache] Apache WILL NOT start without the configured ports free!
2:20:03 PM [Apache] You need to uninstall/disable/reconfigure the blocking application
2:20:03 PM [Apache] or reconfigure Apache and the Control Panel to listen on a different port

[Altrea]

Read this: [Q&A] solving Port 80 in use by PID 4 (HTTP.sys) issue
and this: [Q&A] Changing the Apache default ports