404 Error when creating a new site (localhost)

So I just installed WordPress on my desktop under localhost so that it can be a DEV site for my live one. Everything has gone well until now. When I go to create a new site, it says that it’s successfully created but when I visit the dashboard, I get a 404 – Not Found Error. Why is this happening? Why doesn’t it just create a new site for me to go to.

FYI – Not sure if this matters but I don’t have the .htaccess file in my folders. One didn’t show up even after switching the permalink from default. It’s not even there if I say show hidden files.

Your help is much appreciated!