Can't access web interface, stuff is not working

[Srel]

The issue I am facing:
Hi, I am a complete beginner to this, so I hope this makes sense. I used this tutorial to install pi-hole on Windows 10: https://www.youtube.com/watch?v=iD7StFkr2eg

It all went well, but when the web interface opened in the installation process (prior to step 15 in the doc linked in the video: Install Pi-Hole on Windows 10 Via WSL ) the page did not load.

I tried to use my local ip adress to reach the interface (http://localip/admin) but it did not work either ("The requested URL /admin was not found on this server.")

When I entered the DNS in my ipv4 settings, my internet stopped working properly, so I removed it.

I think I messed up somewhere, might someone be able to help me?

This is the link to my debug token: https://tricorder.pi-hole.net/D8sfqcJE/

Hope this works, I only get a blank page when I open that link...

Details about my system:
Windows 10, using Firefox

What I have changed since installing Pi-hole:
nothing.

[Srel]

So I get this error when I try to start the "Pi-hole Launcher.cmd":

Does this mean port 80 is blocked and I need to forward the port in my router firewall (which is not possible because my router seems to be crappy)?

[Srel]

Okay I feel like I'm way in over my head, but it would be so cool to use this.
Seems like the video I mentioned is very simplified, since it doesn't mention any of the forwarding/firewall stuff listed under "prerequisites" in the doc.Prerequisites - Pi-hole documentation

I'm a bit bummed out, because there is no way I will be able to do everything that is mentioned there without more technical knowledge.

[chrislph]

That error is saying that something is already listening on port 80 on your machine, so the Pi-hole web server can't start. A utility such as this one may be able to help track down what process is using port 80. Then you will have to work out how to close the thing that's using the port and try Pi-hole again. Hopefully it now works.

This Windows port of Pi-hole isn't supported here but the above might get you going. If this is your Windows 10 machine, perhaps another way you can try will be to install the free VirtualBox and use this to create a small Linux virtual machine running a supported OS like Ubuntu. Then you will be able to install Pi-hole using the official installer.

Another way might be, do you have an old machine you don't use anymore? An old laptop maybe that's in a cupboard. You can install Linux on that, it's quite straightforward, and then you can again use the official installer. Just a couple of extra ideas.