This is the A in C major tone as heard in the .hack series.
For those that don’t know, this is a tone that is usually heard in the .hack series whenever there is a system anomaly.
This was a fairly annoying sound clip to find. I had been looking for it personally for a game I was running with White Wolf’s Storyteller System.
So now, those who have been looking for it, here it is, all 5 seconds of it. lol