There are a couple of possible causes, and therefore a couple of different solutions.
1) The first thing I'd like you to look at is a list of all your programs installed.
If there are any programs listed which are unfamiliar to you, I'd advise you to uninstall them
2) Have you visited any suspicious websites recently? If so, those websites may have placed files onto your computer, which allows them to play this annoying audio ad's. You might want to try to clean your temporary internet files
. This can be done in each browser, or by using tools such as CCleaner (be careful though!)
3) There is a serious indication for possible malware on your system, as several (well known) anti virus/spyware program's are unable to detect any issues.
If the above possible solutions have not solved the issue, I'd advice you to start a new topic in the Security > Virus, Trojan, Spyware, and Malware Removal Logs section.
However, don't be alarmed to quickly. If your system is running fine, without any other problems or possible indications for spyware/malware, it may just be a hidden process bugging your system. The experts on this forum will be able to quickly identify the problem and solve it
Hope this helps you out for a start!
Edited by Moc, 21 August 2010 - 10:21 AM.