I found the drivers here:

http://www.fujitsu-siemens.com/support/downloads.html

- Type in the (senic n300 i845gv) in the search and follow the instructions.

- When the driver page opens click on audio and download the zip file.

- Once you are done downloading unzip the drivers on your desktop

- Then open your control panel (Start -> Control Panel) and switch your contol panel to classic view (it is an option given on the left menu)

- Open the System properties by clicking on System

- In the System box click on Hardware tab, then click on Device Manager 

-  In device manager you will see all the hardware installed on your computer. Since your soundcard is not installed, you might find it under the Yellow Questionmark by the name of Multimedia device or audio driver. Once you get there, send me a message and I will give you the details to be more specific, dont want u to waste alot of time trying to figure out or get something wrong.

And if you have hard time with the instructions, send me a message aswell.

It's always the small things that make big differences.