Does it work in another PCI slot? You'll most likely need to reinstall the drivers.
And I know it sounds stupid, but is the card pushed all the way in? Due to some of the crappy cases around, it's easy for PCI cards to not be fully slotted in, and work their way out.
Do other PCI devices (modems, network cards, anything) work OK? If yes, then he'd be a bit silly buying a new motherboard just for a sound card. Be a better bet buying an external USB or firewire sound card, unless he's planning an upgrade anyway.