If you are unable to start the Web Server using Port 80 due to port 80 being already taken, make sure to check what other services are already using Port 80.

IIS is usually the first service to come to mind, but evidently the following Microsoft services can use port 80 too:

• SQL Server Reporting Services (ReportServer)
• Web Deployment Agent Service (MsDepSvc)
• BranchCache (PeerDistSvc)
• Sync Share Service (SyncShareSvc)
• World Wide Web Publishing Service (W3SVC)
• Internet Information Server (WAS, IISADMIN)