The typical problem…everything working great except in IE6&7. The 2nd column gets knocked down below the first. And, no I don’t want it that way for mobile devices.
I want the gray box to fill the width of the browser.
On your second column simply remove the 100% width and it should work correctly, in IE6 however you may need to apply the double margin fix which is just a matter of halving the margin and applying it for IE6 only which you can do with the the underscore hack as seen below: