<link rel="stylesheet"href="C:\Users\Shepard\Desktop\styles.css" />
is referring to a file on your local C:\ drive, is that really the path you want to use? I would expect you really want to link to the styles.css on your server, not the one on your local machine.
See absolute and relative paths explained here
That line might also work better with a space betweeen attributes like this
<link rel="stylesheet" href="C:\Users\Shepard\Desktop\styles.css" />
or, even better, something more like this
<link href="C:\Users\Shepard\Desktop\styles.css" rel="stylesheet" type="text/css" />
For more help with checking your code see the links about validation in my signature line below.
To see why some of your CSS is being ignored, AndrewGSW is right in asking to see your code - both CSS and
HTML would even be better.