no sound after freeze up during gameplay

[nikko]

I had a lock-up recently while playing Half-Life 2. I waited a few minutes to see if the machine would snap out of it, but it didn't so I had to perform a hard reboot, Since that time I haven't had sound on my computer. I don't just mean in Half-Life 2, but in any application: Winamp, Windows Media Player, etc. I checked the most obvious thing, the sound control panel, to see if somehow the mute had been engaged, but it hadn't. I updated the drivers, but still no sound. Then I uninstalled the drivers, and ran the registry cleaner CCleaner. Then I reinstalled the drivers from CD, but I still don't have sound. Has anybody had anything like this happen to them? I'd love to hear some trouble-shooting ideas. Thanks in advance for any help you can provide.

system info that might be relevant:

Win XP Pro SP2
AMD Athlon 64 3200+ CPU
Asus K8V SE Deluxe mobo
Audigy 2 Platinum sound card
1 GB Micron PC3200 RAM
BFG 6800GT OC

Thanks.