System plays an audio file on it's own

First of all, I'm new here so -if I've posted this in the wrong place, please let me know so I can move it.

Approximately 4 weeks ago, my system was sitting idle while I was making supper. Just out of the blue it started playing an audio file that made me think the system played a warning audio of some kind. I could find no reason for it.
The next week, while idle, it played the same file.
The following week it played the same file on approximately 3 different days. It always only played the file 1 time.

Last night it played the same file 4 or 5 times and each time it repeated the file 20 times. the time between each time it played the file was shorter. 45 seconds between the first and second 40 seconds between the 2nd and third and so on until only about 5 seconds between the times. Today, I searched for every .wav file on my system and played it. That was 1,017 files but none of them matched the file that keeps playing.

I've ran Avast Pro, SuperantiSpyware, Malwarebytes and Spybot S/D. Everything came up clean. I've been running each of these everyday for the last 3 weeks.

I'm at my whit's end with this. Anyone have any ideas?

Does it play a message, or is it just music? If it's a message, what is the message? If it's music or some other sound, what is the sound?

Also, you could run MSCONFIG and disable all device drivers except for the Microsoft ones, to see if the audio stops. If it does, then re-enable two or three devices at a time, to see if the sound comes back.

Sorry for being so slow to respond back. I forgot where I posted to and only found it a few minutes ago while looking for a different problem I'm experiencing. I did find the original "problem" which turned out not to be a problem. It was an installed program that I added a long time before and hadn't used. I found it by accident one evening when I wasn't looking for it.

Again, sorry for the slow response.

At the top of the screen are some links you can click on. Second from the right is "subscriptions". Click on subscriptions, and you'll get a complete listing of every post you've ever put here at SevenForums. The ones in boldface are those where someone has posted a comment since the last time you looked at it.

Thank you mrjimphelps. Got it. LOL