I am attempting to make a new website where my client wants the entire website to use a "background image" as the MAIN layout that can be seen at

http://www.nexcheck.mobi/main.html

As you can see, I have some menu bars that are inactive at the moment. Some of the items will be single click menu items that link to another page that will fill the MAIN area. However, the link "Industry" will have 4 or 5 dropdown links that will also open in the MAIN area (where the guy is standing).

I have tried creating hotspots, slices, sprys, etc.. using Dreamweaver, photoshop, Fireworks, etc... and can't get it to work right because I need to use this actual background image as the layout.....

What would be the best way to go about making these menu items active and adding a drop down effect to the "Industry" item so that I stay within the images look?

I have searched and watched tutorials galore and I still can't seem to get these menus active and have drop downs without messing up the look of the overall background image.

Any help would be greatly appreciated.