Hi, I'm from Argentina and a need desesperatly some help!
After installing the game Halo and directx 9 and rebooting the computer and can't open any folder, when i tried to do so, nothing happens.
If anyone could help me, i would be very please
Thank you!

try uninstalling Halo and directx 9, just to see if that works!!

you cannot uninstall directx, but try uninstalling the game or use system restore to go back to before you did.

This happens after you make changes to you system that affect the video drivers, changing BIOS settings (video fast write, video BIOS cache ect) or installing new versions of DirectX. You will need to uninstall the video drivers and reinstall them Sometimes it is necessary to turn off video hardware acceleration before reinstalling the drivers. After confirming the drivers are working properly you can turn video acceleration back on. Before reinstalling the driver its a good time to check for the latest video card driver.

P/S
When this happens and you can not access or click on a folder or directory to open it, right click on the directory or folder and pick "Explore" from the menu. The directory or folder should open in a new window. This will allow you to access "Control Panel" from the "Start Menu" to uninstall the driver.