After looking for a solucion all day i finnaly found one that work for me, I have a ATI Mobility Radeon HD 3670 on a Windows 7 64bit and it wasnt working at all

11.5,12.3,12.4, 12.4a dirvers versions did not fix a thing

i found this thread on, where they give out the 12.4a fix and the mobile version:

It is a modded version of the 12.4a fix so install it at ur own risk, but its only modded to work with the mobile version of the cards

Theres list of all the suported cards on the post

What i did:

    I had 12.4 installed already on my pc

    I didnt unistall anything at all

    I ran the modded for Mobile and installed it, got a warring about some ID validation and manufacture ( warrning was from from windows), said to go ahead and install it

    after it installed correctly i ran diablo and DONE!

no reboot, no uninstall, nothing

hope this helps out any frustrated AMD diablo player ;) maybe i just got lucky