Reinstalled Windows, Sound card error

My version of Windows XP professional stopped working, so I installed the Home Edition and now I cannot play sound files. I get this error message:

Cannot play back the audio stream: no audio hardware is available, or the hardware is not responding (Error= 80040256)

My sound was working perfectly before the computer crashed but now I can't even change the audio settings, because it thinks I have no sound card.
The bad news is my computer was built by a friend of mine's brother, so I'm unsure as to the model of the soundcard, but I might be able to find out from him if it would help.

Thanks,
Keith

 

have you checked the Device Manager? RIGHT click My Computer, choose Properties, then the Hardware Tab and click on the Device Manager button. How does that see your sound card?