Jamal,
When you issue the following command from a command prompt: netstat -an
You are looking to see if there is something already binding to port 6080 on your server. If nothing is using port 6080, then you can check off one of Richard's suggestions.
I know nothing about Windows 8. I do know that in Windows Server 2008 R2 I had to allow the port 6080 in the firewall, if you have the Windows firewall turned on.
Was your ArcGIS Server 10.2 started before? In other words, it "was" running before this post, right?