Since updating to the latest windows 7 updates on 9/12/12, including an optional update for my graphics card, i've been getting the following error message on bootup:

Xvid Video Codec has stopped working
Appcrash
autoupdate-windows.exe
nvinit.dll - unloaded

I click the option to check online for a solution, but nothing happens.
However, I can still play the mp4, mpeg and avi files I tested (about 6 files).
And when I load a few of these files into gspot it reports that the xvid codec is installed

Also, info in windows update indicates that the optional fix I installed for my graphics card was successful:
nvidia graphics adapter: WDDM1.1, WDDM1.2, other hardware - NVIDIA Quadro 1000M

I have four copies of nvinit.dll on my system. Properties for them don't show version numbers but do show this info:

C:\swtools\drivers\video\nvidia - created: 11/24/11 modified: 6/1/11 accesed: 11/24/11
C:\program files\nvidia corporation\Installer 2 - created: 2/18/12 modified: 8/13/11 accesed: 2/18/12
 C:\program files\nvidia corporation\Installer 2 - created: 11/24/11 modified: 6/1/11 accesed: 11/24/11
 C:\drivers\win\video\nvidia - created: 2/18/12 modified: 8/13/11 accesed: 2/18/12

I'm not sure how to correct the bootup error. Should I roll back to my restore point before updating windows? Or is there a fix? And how can i find out which version of the codec I'm using?

Thanks very much for any and all help.

Ellen