Sounds like maybe there is a problem with bios settings.
It could be they were changed because the PC originally had an extra sound card fitted and settings changed in bios to accomodate this.
Difficult to tell without actually having the box in front of me to play around with.
Have a check to see what settings are showing for plug and play too, also any allocation of IRQ numbers etc.
One last thing to check is trying different PCI slots for any add-in cards just in case a shared resource is behind the problem.
One solution if conflicts are to blame is removing sets of devices in device manager and then letting XP re-add them all back as this changes the way the rersources are allocated.
You may also need to check for an update for the bios itself as this often happens with older boards and XP.
EDIT: LOL Sorry forgot you are not on XP because of the low memory so maybe consider adding more and re-trying XP so the above tips can help
