ICE plays a sound when it blocks activity it doesn’t trust and the default sound is a ‘Slap’. (I still think it’s funny every time I hear it)
Many companies, configure their ‘Is it time to update our program?’ to run at Windows Startup.
When these program attempt to update your system ICE will block them and hence why you hear the slap.
It was tempting for us to add a feature that would allow these update programs to work as intended, but we can’t since a great many crapware programs configure themselves to reinfect the computer at startup.
If you don’t like the ‘Slap’ sound, you can change it on the Sounds tab of the options dialog.