Error: API mismatch: the NVIDIA kernel module has version 295.40, but this NVIDIA driver ...

现象：更新Ubuntu到12.04以后，图像化界面出不来了。(Error: API mismatch: the NVIDIA kernel module has version 295.40, but
this NVIDIA driver component has version 295.49. Please make sure that the kernel and all NVIDIA driver components has the same version.)

解决方法：卸载显卡驱动，重新安装。

1.

sudo
apt-get purge nvidia*

  卸载现在的驱动

2.sudo apt-get install nvidia-current-updates-dev

3.reboot

Looks like you didn't uninstall your previous driver version. This can happen because 

nvidia-current-dev

 is
of version 

295.40

 and 

nvidia-current-updates-dev

 is
of version 

295.49

 as
reported. 

If you've installed the nVidia driver from Ubuntu's Additional Drivers dialogue

, try 

sudo
apt-get purge nvidia*

 then try reinstalling by 

sudo
apt-get install nvidia-current-updates-dev

 then reboot. 

If you have used the 

.run

 file
from nVidia's website

then go to a console by pressing Alt+Ctrl+F1 and
then run 

nvidia-xxx-pkg1.run
--uninstall

to remove the previous driver components. Now give a reboot and see if that works.
If not, then execute

sudo
echo "blacklist nouveau" >> /etc/modprobe.d/blacklist.conf

 so that the default nouveau driver
for nVidia chipsets are not loaded
4000
instead of proprietary one. Finally install packaged binary drivers by 

sudo
apt-get install nvidia-current-updates-dev

.

http://askubuntu.com/questions/145195/nvidia-driver-problem-after-updating-to-12-04