No sound card in Sounds & Audio Devices?

I recently bought a Dell Dimension 4600 with Windows XP Pro SP2 re-installed. The sound worked fine for a week but now there is no audio. When I checked in the Device Manager under Sound, Video and Game Controllers, I saw ‘SoundMAX Integrated Digital Audio sound card’ listed. Clicking its properties says ‘Device is working fine’.

But when I check the same in control panel, SoundMAX is nowhere in Sounds and Audio Devices on the Audio tab. How can I get the SoundMAX Integrated Digital Audio device to appear in the device drop-downs on the Audio tab of the Sounds & Audio Devices dialog? Please help.

Forget it. Remote Desktop is the cause. The sound card works with UltraVNC.