I just got this problem today, since it showed up after Norton requested reboot I blamed Norton.
But it wasn't Norton, I removed Norton, rebooted -> problem still there.
netstat -nao was showing that PID 4 owned my port 80 connection.
I then went to control panel,
then "Turn Windows features on or off"
then unchecked Internet Information Services.
Rebooted, the problem went away.
My xampp server is running ok now.
I don't ever remembering turning IIS on in the first place.
I had been running many months before this happened.
I still don't know what caused it in the first place.
Maybe a previous windows updated enabled iis and my reboot turned it on, I don't know.