Do not think about ending the System process. It is critical to the functioning of Windows.
According to a similar question on Stack Overflow, below services should be checked for the problem of System process ("NT Kernel & System"; PID: 4) using HTTP/80 port (and HTTPS/443 similarly):
- Web Deployment Agent Service
- SQL Server Reporting services
- World Wide Web Publishing service
- IIS Admin Service
See if you have any of the above services and running. If you do, check their configurations.
(Yes, IIS is on the list too. You might already have IIS installed along with other applications but you didn't know.)
If you can't figure it out, you may also try browsing http://127.0.0.1 (port 80) and https://127.0.0.1 (port 443) to see if there is any information indicating which applications/services might be serving the web pages.
After finding out the causing applications/services, either remove them from the system or change the port numbers as you see fit.