[ubuntu] How cab I detect my Graphic Card works proper ?

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http://ubuntuforums.org – It's 2 year I've started using ubuntu. In ubutnu 10.04 until ubuntu 11.10 anything was Ok with my Graphic card, But when I migrate to ubuntu 12.04 I had a corruption in my graphic card and I paid expert to repair it. It was Ok with ubuntu 12.04 in continuous but when I upgraded to ubuntu 12.10 I'm never able to install my nvidia. My graphic card is Geforce 8400, and the driver I install is Nvidia 173. I decided to back ubuntu 12.04 and this time I have same trouble there too. So what's your advice ? How can I use my Graphic Card properly ? (Hardware)