My mom needs help.
By the description is sounds like the card my be dead but I can't really tell for sure.

Here's the email she sent me.

Quote (Mom @ Nov. 30)

My older XP machine is having a unique problem.   1) I can hear system sounds (start, critical stop, beeps, etc.) 2) Some of my music programs try to work but give error messages. 3) The sound icon will not show up on the task bar 4) The sound setup in control panel indicates that there is no sound mixer available.  When you click on properties it tells you that you can enable that device (but it never becomes enabled nor configurable), and it tells you that the device is working properly. 5) I have done a system restore...same problem exists 6) I have rebooted...same problem exists. Is my sound card bad?

Also, she's about an hours drive away so I have no first hand knowlege of what's going on, so any questions yall ask, I'll have to email her and ask.

more likely windows isn't recognizing the hardware and its loading the wrong driver. it seems like the card still works (she can hear sounds on the desktop).
try removing/reinstalling the driver first.
if its a hardware issue, it could be either the soundcard or the motherboard.
try moving it to a different slot first.  and if that doesn't solve anything then look at replacing the card.

Drivers would have been my guess as well.