drivers - The system is running in low graphics mode?

Hi there. I've dual booted my device with Windows 8 pro and Ubuntu 13.04
I've done all updates by the following commands:

1. sudo apt-get update


2. sudo apt-get upgrade

Then I've installed the additional drivers for my nvidia graphic card to support for it in the additional drivers menu in settings.

I've installed the nvidia driver 310 (propitiatory, tested).

But recently when I boot to ubuntu my screen gets into terminal like mode and starts displaying some code lines like:

1. wlan0: inserted not in use


2. card display mode etc. , lines

And no key works when I press the "Enter" key or the "power key" I'm getting a dialog box like "the system is running in low graphics mode".

Then no key works nor my mouse, touch pad. But my problem fixed when i reboot it.
Please any one solve this problem.