Need to make menu bar not float and accomodate screen resolution

[Lauren]

I am using the script from this site to create my menu bar for my website. I
was originally viewing my site at 1024x768 and it looked great. Then I
changed it to 1280x1024 because that is what my boss uses and then the menu
went way off the page overlapping with my background edging I have going down
both sides of the page. Below is the code that is telling the menu where to
reside. Is there any way to get it to adapt to both resolution settings?

#menubar{
position: absolute;
/* width declared by using uiMenubar.setWidth("auto",i); */
left: 100px;
top: 150px;
background-color: #0A86AA;
padding: 0;
border-width: 1px;
border-style: solid;
border-color: #3344ee #000033 #000033 #3344ee ;
clear: both;
z-index: 200;
white-space: nowrap;


Thanks,

Lauren