Need help: How to remove proxy server settings from my computer? or What's the easiest way to remove

If you’re worried about leftovers after removing the proxy, try this:

After turning it off in settings (like others said), open Chrome/Firefox and check their proxy settings too. Sometimes browsers override system settings.

Also, this site has a cool tool to check your current proxy status: whatismyproxy.com. Helped me confirm mine was fully gone!