Windows XP audio device disappears from audio properties, suspected .dll problem

I am facing problem with Windows XP here. I am not able to work with some audio files. When I try to play some mp3 files there was no audio at all. The device simply disappeared. I checked inside Device Manager, but I cannot find anything related to the audio tool. I am trying to run windows update and that also is not working at all. I am here using a PCI sound card. I changed the slot but still audio is not working.

If there was problem with the sound card, then it must have detected. If it is not then surely the sound card is damaged. If you want you can test that in some other pc also. You will need to buy a new one I think. The most you can do is run windows update and check.