I repeatedly have noises coming from my computers: door slamming, door creaking open, women's screams. Seems that malware audio files are playing intermittently. Norton and Spybot have no effect. These have now spread over my entire home network. Anyone heard of this or know how to remove them?

I haven't heard of malware doing this but here's some ideas for you.
To make sure everything is running fine run both anti virus and anti spyware apps in normal AND safe modes. (make sure that they are updated first ! ;)) (AVG is good and free AV)
(A couple of good removal tools are Spybot and Adaware)

ALso an on line virus and spyware scanner is Trend Housecall

Just a note; actively running two AV's on one machine can cause problems.
So if you are thinking about it make sure your current one is disabled first.
SAme thing applies to online scanners as well.

If this doesn't work can you please let us know more of the symptons and your computers setup.

Do you have kids? (or other jokers) Is it possible they may have loaded some kind of windows theme for a laugh?

Just a thought, to check right click your desktop and click properties, and try changing themes in the themes tab.