WAMP not updating changes in my files

So I am a novice at Web development and I am trying to create a website and am using WAMP to test out my PHP code and such. The issue I'm running into is that when I change my file, and try to refresh my localhost page on my browser, it gives me a file not found error. When I close out the localhost page and reopen it, the page that I changed appears properly and is updated properly.

I was just wondering whether there is an issue with my WAMP or whether having to open a new localhost page is necessary every time a file is updated?