Thanks, I may try that but now I realize that each time this happens, it knocks out sound on my computer.
Even though I've removed Avast and rebooted, I have no sound. The last time this happened was a few weeks ago when I first went from the beta to released version of Win 8 and encountered the BSOD problems.
Today's was the typical aswnet.sys problem and I've no idea how it can be knocking out my sound. No problems in device manager, no error messages, sound seems to be working as far as the OS is concerned but I don't actually get any sound.
DXDiag attached in case that helps.
Edit - Reinstalling the sound driver and rebooting seems to be the only way to restore sound.