Windows 7: Control Panel Display Settings

I have two monitors - I use one primarily.
My normal setup in Display Settings is "Show Desktop only on 1" - this works fine.
If I switch to "Extend These Displays" my desktop moves over to the second monitor and my main monitor shows the desktop background image with no icons.
How do I get the opposite to happen? I want my normal desktop to stay on monitor one and just the background to be extended onto monitor two.

do you have the Nvidia control panel under your desktop "Right Click" options?

If you do, open it up and choose the "Set up multiple displays " option.

You should see a grey box with two numbered smaller boxes in them.

Swap them by holding a left click over one of the numbered boxes and moving to the other side of the grey box.

Thanks - I have an ATI 5770 but that's not the problem maker. This is a new problem that started when I installed a new monitor - in this case a Dell U3011. Before this I had a Dell W228 that worked "normally" - meaning that when I selected "extend these displays" my main monitor would stay as it was and the desktop background would just be extended onto the second monitor.

Oh, sorry. Your system specs say that you have an Evga 8800Gt....

I'm not familiar with the ATI control panels. But you could always just swap the monitor cables in their ports....

Ooops - I should update my profile - that was 2 cards ago.

The "second" monitor is actually a projector run off of a USB connection.

Have you tried Right clicking on the desktop, and selecting "Screen Resolution" ? It will give you the same option to swap the physical location and main monitor.

Yes, that shortcut just takes you to the Win "Change Display Settings" box.

So what happens when you grab box 1 and swap places with box 2 and apply?

Nope - doesn't allow swap - I can move the number 1 box but it jst snaps back into position. Can't move the number 2 box at all.

Yep - I'm stymied too.