Ok,

This one has me stumped. A customer brought in a PC we had sold them within the past 4-5 months. It's an AMD Duron 800 - MSI6330 Motherboard - ATI 8MB AGP - 128MB PC133 - Win98SE. It is using the onboard AC'97 sound card.
I go into Windows Media Player 7.1 or the standard version that comes with 98SE. I can play MIDI files from the hard drive (Beetoven's 5th Sym etc.) fine. When I go to play any WAV files it tells me that there is no sound card. It also happens when I try to play a CD in Media Player. I can play CD's through the Windows' CD player. I have reinstalled the sound card software numerous times, I've checked for updates from MSI. Any ideas?