You don't need to remind me why Acer is not a good computer. Just take a look at the drivers in support. With a Dell you will have a list of drivers, but Acer just stops supporting if they had any support at all.
If that XP Pro is 64 bit then you will be lucky to find drivers for any thing that is not the main part of the main board. Windows XP 32 bit is easy to find drivers, but there may be too many to dig through to find the best one that actually work. So it is great the drivers were found, but you should save them on some kind of drive.
With XP most drivers has a date, and unless you can edit the driver to change that date the driver will not work. I always force it to work even with a warning, because everything was original, and it was just MS Greed that keeps them from working.
I'm almost certain the nvidia audio is not the primary audio device and is for use with the HDMI output I would assume your computer has. Have you installed all the drivers for your system from the manufactures website?