problem with sound

Hi,
I have a HP-PAVILION PC with 657 MHZ Intel III Processor, 192 MB DDRRAM, 40GB Hard Disk, Windows XP OS.

Intially when i bought my PC 4 years back, it had 10 GB HDD with Win98SE OS and it had Aureal (Au8810) sound card. The upgrade was done last year and i was not present when the upgradation was done.

From yesterday my sound is not working at all . even the system sounds are not working and i am getting the error message: There may be no sound card or sound card drivers may not be working".

When i veiwed my system info, i found the audio device listed as "Unimodem half-duplex audio" which i read in a site is not a proper sound device.

Now what should be done?? How to check if my audio device has changed and how can i reinstall my previous sound device??
or is it ok to continue using Unimodem half-duplex audio as my audio device and try reinstalling its drivers??

Thanks in advance.

This seems to be a device-driver problem, after installing sound card you may have installed other device whose device-driver is conflicting with your sound card device driver. Download a new driver for your sound card reinstall it.

Hi,
thanks for the reply.

As i was contemplating reinstalling the drivers, a couple of days ago, the sound started working properly by itself and i have not faced the problem since then

Dunno how it got solved (as i had not done anything) but happily it is working fine now