There was a previous thread that had been previously posted but now has been locked to presenting any additional solutions. So this is actually an additional solution, not a question to the police siren running in the background. I have a Gateway Laptop running Win 7(64bit) with a AMD Athlon II Dual Core M300(Caspian) with a WiFi connection. It is about 2 years old. Three weeks ago I reformatted my HD and reinstalled everything. I started noticing the police like siren in the background that started about a minute after I booted up my computer that would go for about 15-30 seconds and then quit. It would do it again approx every 30 miinutes, regardless whether I had any programs, browsers, etc open or closed. I ran virus programs, registry programs, and other malware apps. It still continued. Yesterday I opened the volume mixer (Right click on the volume icon and choose open volume mixer). I noticed a slider control Which I hadn't seen before: mpg123. I waited till the siren went off again and clicked on the mute for that slider and it stopped. I then started to think of any programs which were on my computer that might have that siren sound associated with it. I then remembered that I had the Prey open source antitheft program, one of the ones that I had re-installed. I went to my programs menu and selected the 'configure prey' option. When the Prey Congigurator Menu opened I selected the 'Manage Prey Settings' option and next. I made sure the 'Wifi autoconnect' option was checked and hit apply. It said successful. I waited for an hour and heard no more siren. I then went back to the volume mixer and noticed that the mpg123 slider was no longer there. Of course, it probably had disappeared after I had reconfigured the Prey settings. So far the siren has no longer returned.