404 not found

hi everyone. I’m new to wordpress and it’s sure giving me hell. I went through the installation and for the 1st time it ran perfectly well. I began building a website. Then, next day when I tried to log in, all it gives me is “404 not found. The requested URL /wordpress/wp-login.php was not found on this server.

Apache/2.4.9 (Win64) PHP/5.5.12 Server at localhost Port 80″.

I’m not sure why it would do that. I didn’t change anything.

Also, I’m not sure which version of WP I’m using. Any ideas how to check? Try not to get to technical with me, as I’m pretty amateur with these sort of things. It might be the simplest thing to untangle, but having no clue makes it quite a pickle for me.

Thank you.