Menu na celou šířku

Těžko radit, když nevidím konkrétní kód.

Zkontroluj hodnoty u margin a padding.

HTML kód:

<ul id="menu-bar">
 <li class="active"><a href="#">Home</a></li>
 <li><a href="#">Products</a>
  <ul>
   <li><a href="#">Products Sub Menu 1</a></li>
   <li><a href="#">Products Sub Menu 2</a></li>
   <li><a href="#">Products Sub Menu 3</a></li>
   <li><a href="#">Products Sub Menu 4</a></li>
  </ul>
 </li>
 <li><a href="#">Services</a>
  <ul>
   <li><a href="#">Services Sub Menu 1</a></li>
   <li><a href="#">Services Sub Menu 2</a></li>
   <li><a href="#">Services Sub Menu 3</a></li>
   <li><a href="#">Services Sub Menu 4</a></li>
  </ul>
 </li>
 <li><a href="#">About</a></li>
 <li><a href="#">Contact Us</a></li>
</ul>

část CSS:

#menu-bar {

  width: 100%;
  min-width: 300px;
  margin: 0px 0px 0px 0px;
  padding: 6px 0px 0px 0px;

  height: 34px;
  line-height: 100%;
  border-radius: 0px;
  -webkit-border-radius: 0px;
  -moz-border-radius: 0px;
  
  /*     STÍNY
  box-shadow: 2px 2px 3px #666666;
  -webkit-box-shadow: 2px 2px 3px #666666;
  -moz-box-shadow: 2px 2px 3px #666666;
  */

  background: #0077FF;
  background: linear-gradient(top,  #0077FF,  #0077FF);
  background: -ms-linear-gradient(top,  #0077FF,  #0077FF);
  background: -webkit-gradient(linear, left top, left bottom, from(#0077FF), to(#0077FF));
  background: -moz-linear-gradient(top,  #0077FF,  #0077FF);
  border: solid 1px #006BE6;
  position:relative;
  z-index:999;
}

A to menu <ul id="menu-bar"> máš vložené v nějakém nadřazeném DIVu?