Installing on a pc failed

[Drachsi]

I tried to install today and get the error message,
"07:43:50 [main] Initializing Modules
07:43:50 [Apache] Problem detected!
07:43:50 [Apache] Port 80 in use by "Unable to open process" with PID 4!
07:43:50 [Apache] Apache WILL NOT start without the configured ports free!
07:43:50 [Apache] You need to uninstall/disable/reconfigure the blocking application
07:43:50 [Apache] or reconfigure Apache and the Control Panel to listen on a different port
07:43:50 [main] Starting Check-Timer
07:43:50 [main] Control Panel Ready"

What does it mean and what should I do next? also how can I check I have admin rights?

Regards
Drachsi

[Nobbie]

viewtopic.php?f=16&t=69784