Multimedia audio controlers drivers not installed

Hi experts can any one give me the solution for my problem.
Recently i have formated my HDD and installed Windows XP SP2.but OS is working properly and i could not be able to run music files and i am finding the that the sound devise is not installed. i have seen the devise manager and there i found a "?' in yellow as multimedia audio controllers.and i tried to install the drivers but it is not working. it is asking the source such as CD or Floppy or another location where the drivers are located.
i got sound card on mother board it self and my processor is 1.33GHz.

You need to identify the motherboard and from that visit the maker's website, where you will find the drivers you need for XP.
You can find out your motherboard maker by looking at the board itself or at the opening screen when you boot the machine - press the pause/break button to stop the boot process while you write the numbers down.