a: link help

I placed an anchor tag around my banner and there’s a weird strip that shows up when my house hovers over the image -only in Firefox and not IE.

So I made a new div class for the a tag up in the header

a:top:link,a:top:visited,a:top:hover{
text-decoration: none;
background: none;
}

But it still didn’t take stop the background color hover.
I tried <span> but that didn’t work either… =(

Is there anyone out there nice enough to help me with the code?
Thank you in advance!
http://www.no-teriyaki.com