Civ 5 wont run on Directx 9

[turrumbi]

I have installed Civ 5 and it runs on Directx 11 (recommended) fine but i cant Alt+Tab.
When i try to run it on Directx 9 it "stops working" almost immediately. I would like to be able to run it on DX9 for increased speed and for the Alt+Tab facility.
I have an i5 and ATI 5670 on Windows 7 32 bit.
Help would be much appreciated!
Thanx

 

[timtofly]

Have you tried to delete local content and re-downloading it? Or windowed mode?

 

[turrumbi]

Thanx for the comments. How would i go about either of those procedures?
thanx again

 

[timtofly]

Windowed mode is one of the graphics setting in advanced settings mode when you set up a game under the graphics tab.

Local content can be checked or re-downloaded if you right click the title name in steam and pick properties at the bottom. The next box that pops up choose the second tab that says local content. The choices are in that box.