Need some help using CSS Rules and Positioning Image Place Holders

Question

Evening all,
I need to get this done by tomorrow so some speedy help would be very much appreicated!
I'm doing a website for an IT company, and as you may/may not know, support for XP and Office 2003 is dropped tomorrow - they want a button in the header of their site which basically says 'click here for upgrade advice' and when you click on it you're taken to a page telling you the benefits of upgrading. They want it to look like the mock up below:
I've had a right old job even getting the button (it's in PNG format) to go above the BrownTech logo. I inserted a placeholder, linked it to the PNG file, and then I made a custom CSS rule/class called '.header_fltrt' to put the image in and position it in that place, directly above the BrownTech logo.
To get the upgrade button in the desired position, here are the 'Box' CSS properties I used for the .header_fltrt CSS rule.
It's worth noting that the dimensions for the header itself are 960x235px, and the BrownTech logo is the background image for the header class (and is 960x235 in dimensions).
The problem I am having is that when I view the page in Design Mode in Dreamweaver, it looks fine, but when I view it in Live View or in a web browser, it looks like this:
As you can see, the upgrade button is not even visible!
Furthermore, when I go back into design mode on Dw, when I click on the upgrade button, I don't get any placeholder properties like I do when I click on green logo in the top left (which by the way is just a link back to the index page).
I'm not sure why this is but I cannot find any way to resolve it. I've even tried putting the BrownTech logo on a transparent background thinking that the block white background may be covering the upgrade button, but that's not the case.
Sorry if I haven't explained it very clearly. Hopefully you can see my problem.
Any help in etting the upgrade button to preview in the correct place would be very much appreciated!

Answer 1

Try this in place of what you have now.
.header {
    background-color: #FFFFFF;
    min-height: 335px; /**adjust as needed**/
    width: 960px;
    background: url(../assets/banner2.png) no-repeat;
.header_fltrt {
/**no floats or positioning required**/
    width: 552px;
Nancy O.