Help please .... My sound card does not present

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http://askubuntu.com – Since i have got my laptop ( Dell - Latitude E6510 ) back from grantee ( which they change its motherboard ) My laptop worked fine for couple days ... but after couple days my sound card does not work in either windows or ubuntu 12.04 ... I have re-installed my both OS'es and also recently from desperation i remove my Windows OS and only installed the ubuntu 12.04 but still not sound card(see the image) .... :( I need to mention sometimes(few times of 100 times) when i reboot my system's sound works... I am totally desperate ... I need to know : 1) Is it related to my new motherboard? 2) I (HowTos)