Yeah, I intalled 9755 package before and remove it by in the Menu later.
I've removed some package whick I think will be related to 9755, and reinstalled the 7185. And the error still exists and 9755 still appeares in nvidia-bug-report.log.
Could you give me any advice how to remove the 9755 package completely?
Though I still don't know how to remove the 9755 package completely, I know one basic method: remove all of the system and reinstall it.
After that the problem is never occured.
But why my screen resolution is only 800*600 and refresh rate can just reach 60Hz ?? It seemed to be lower than before. what can I do?