my page is usually that:

normal links: red
hover links: orange with white background
visited links: red

When i put my cursor over a link that has not been visited yet, it's normal( text changes orange).. but when i put my cursor over a link that has been visited, it changes background, but the text doesn't change into red.. why?

If you have your visited links coding after the hover, you need to put it before that and after the a:link. Example:

A:link { text-decoration: none; color: #color; }
A:visited { text-decoration: none; color: #color; }
A:hover { text-decoration: none; background: #color; color: #color; }

yay it works! thanks!

but why does the positioning of code affect the page??

"usually" the positioning of the coding should not affect the outcome. in some minor cases, it does. this is one of them.

(other cases usually involve trying to conform to Netscape4, but that is a dying version and not worth mentioning.)