Update: this driver is reported to work under Windows 10
Since Dell is unable to provide a recent Catalyst release for its Dell Inspiron 9400 for Vista or Windows 7 and explicitly forbids ATI from distributing one, here it is.
Download Catalyst 8.12 for Inspiron 9400 (32-bit)
Note: The Inspiron 9400 is also known as Inspiron E1705 in some countries.
Catalyst 10.2 has a bug related to laptop panel scaling which is why I’m providing 8.12.