Connection server - Port 80

Hi there

I am having problem with installing connection server (Security Server) on a virtual machine after few initial steps it failed as

"TCP port 80 is already in use. This port needs to be available for product to be installed. Please removed any software the might be using this port and try again."

I used netstats to find which programme is using port 80 and revealed that Systems using it.

Any Idea how to close port 80 in order to install Connection Server.