Q:

How do I know whether my graphic drivers are installed or not

I have installed Ubuntu 11.10 on my lenovo laptop and found a "chip" image on the top of the screen. It showed me to install 3 drivers 

ATI/AMD Proprietary FGLRX graphics drivers (post-release updates)
Broadcom STA wireless drivers
ATI/AMD Proprietary FGLRX graphics drivers

When I installed 1st one, it showed me some error so, I installed 2nd one it was successful. I went to 3rd and it failed 1st time and later it worked.. After when I came back and found that it isn't not installed.
I think these are for my ATI Radeon graphic drivers but don't know why its happening.
If even found the "System Info" isn't showing any information about graphics.
So, how do I know whether my graphics are installed or not and if not how do I?

A:

Try running fgl_glxgears. If the driver is correctly installed, you should see an animation of a cube looking like this:

If you get an error, that means the driver is either incorrectly installed, or not installed at all. In order to install it, follow these instructions.

