The main difficulty in the determination of the sound card in the laptop is that out of its data by regular means Windows do not always work, so it is more convenient to use third party tools. One of the best programs in this class is Aida64 (Everest), which allows to obtain very complete information about the computer. Find the program on the Internet.
Install the program Aida64, check the installation file for viruses and if none is found, start it. Select in the left column "Computer" "summary information". In the right part of the window you will see total information in the computer, locate the line "Multimedia" - "Audio adapter". You will see the model installed on your laptop sound card. For example, Realtek ALC272 @ ATI SB750 - High Definition Audio Controller. Knowing these information, you can find sound card needed drivers and install them.
Good opportunities for determining what equipment has the program Astra32, download its free version you can on the manufacturer's website: Available in two versions: with an installer and without. The first is installed on the computer, the second just unzip to any folder and run from it. The program gives a lot of useful information on computer hardware, operating system and installed programs.
You can try to determine the model of the sound card using standard Windows tools. To do this, open "start" - "All programs" - "Accessories" - "system tools" - "system Information". In the opened window, select "Components" - "Multimedia" - "Audio device". Copy the line with the IP of the PNP device, select it with the mouse, open the menu "edit" - "Copy". Now enter the copied string in a search engine – there is a high probability that the links given to you will help to identify your sound card.