Data Execution Prevention with .avi file

You can turn it off.

http://support.microsoft.com/kb/875351


UPDATE:

http://support.divx.com/faq/view/supportFAQen001/The%20DivX%20All%20In%20One%20Fix%20V1.81

Run the DivX All in One Fix utility. Uncheck all options except for "Explorer crash when open a folder".

Overcoming XBOX 360 Live Halo 3 NAT complaint

Playing Halo 3 online complains about NAT being Secure as opposed to Open.

Netgear WGR614 v7.

Upgrade router firmware to latest version.

Set NAT to Open.