http://bugs.winehq.org/show_bug.cgi?id=23683
--- Comment #5 from David aim_here2002@yahoo.co.uk 2011-05-28 12:31:49 CDT --- Created an attachment (id=34941) --> (http://bugs.winehq.org/attachment.cgi?id=34941) Assassin.ini file; breaks slightly slower than the default one
I have this problem too, on an ATI 4870, but with a little jiggery-pokery I can get slightly further.
When the game is installed, the Assassin.ini config file (where the graphics options are stored, among other things) is almost totally unpopulated, and presumably when starting up, the game begins with nonminimal defaults, which cause the breakage.
By downloading someone's posted-on-the-internet Assassin.ini, and tinkering, I was able to get past the initial white screen lockup, and traverse a few options, including setting graphics options and creating a profile. However, clicking 'New Game' goes back to a lockup, similar to the first one, but with an added cursor on the screen. I like to think of that cursor as a sign of progress.
The file can be found in c:\users<whatever it is you call yourself>\Application Data\Ubisoft\Assassin's Creed\Assassin.ini
The line that caused the problem was "PostFX=1". Replacing it with "PostFX=0" gets me past the first white-screen lockout.
Maybe someone can use this info to investigate a bit further and find out what the problem is, or at least tinker enough to get a workaround