Motherboard on its last legs?

Well, I've had this Asus M2n-SLi Deluxe for who knows how long. Recently the onboard sound has died, (or so I believe), so I stuck in an old Creative Sound Blaster Audigy SE, and I had to switch PCI slots to get it to recognize and install the drivers automatically. Okay, no big deal. But since then I've been leaving my PC on all day and when I come home the sound doesen't work. A reboot fixes this. Today after about 1:30hrs of using the PC the sound stops, I reboot and it's fine. A few days ago the POST time was slower than normal, but that seems to be fixed now. Just wanted to know if this was something to worry about, because I might be giving this motherboard to a friend, and it needs to work. Thanks. If it's just the soundcard problem that's fine, I can always pick up a new cheap one. Thanks for any input