I have a folder called styles set up for the .css files.

<link rel="stylesheet" href="styles/myStyle.css" type="text/css" media="screen" />
<link rel="stylesheet" href="myNav.css" type="text/css" media="screen" />

The styles for the Navigation Menu are written in the myNav.css file. This file is acting strangly as it will not link to the website pages when it is deposited in the styles folder. When I place it in the styles folder I call it "styles/myNav.css" just as I would with other style sheets.
Why can this be ?