At completely random intervals I get a sound like a camera shutter clicking and taking a picture, sometimes it won't happen for an hour or more, sometimes with 30s of one another, and it can happen regardless of what program I'm using (Firefox, poker clients, video games, desktop).

I had this problem several years ago but after reinstalling Windows it hadn't happened again until recently. The only piece of software I haven't put on my new copy of XP is I believe Zone Alarm Pro, so I thought that might've been the culprit but obviously not. I ran Spybot with nothing coming up, and I run a pretty tight ship I think, never clicking on links I'm not 100% sure of, and running Firefox with noscript at all times. The only recent pieces of software I've added since it started up again was Cake poker and Pokerstove, the former I didn't have on my previous system install.

Is this some random Windows feature or should I be worried?

EDIT: here's the hijackthis log

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 3:52:22 AM, on 3/7/2009
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP3 (6.00.2900.5512)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\WINDOWS\system32\LEXBCES.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\LEXPPS.EXE
C:\Program Files\Creative\Shared Files\CTAudSvc.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Java\jre6\bin\jusched.exe
C:\WINDOWS\system32\CTXFIHLP.EXE
C:\WINDOWS\SYSTEM32\CTXFISPI.EXE
C:\Program Files\Logitech\GamePanel Software\G-series Software\LGDCore.exe
C:\WINDOWS\system32\RUNDLL32.EXE
C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
C:\Program Files\Logitech\GamePanel Software\LCD Manager\lcdmon.exe
C:\Program Files\Common Files\InterVideo\RegMgr\iviRegMgr.exe
C:\Program Files\Java\jre6\bin\jqs.exe
C:\Program Files\Logitech\GamePanel Software\LCD Manager\Applets\LCDClock.exe
C:\Program Files\Logitech\GamePanel Software\LCD Manager\Applets\LCDCountdown.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\Program Files\Logitech\GamePanel Software\LCD Manager\Applets\LCDPop3.exe
C:\Program Files\Logitech\GamePanel Software\LCD Manager\Applets\LCDMedia.exe
C:\WINDOWS\system32\wscntfy.exe
C:\WINDOWS\system32\PnkBstrA.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Documents and Settings\Administrator\Desktop\CoreTemp\Core Temp.exe
C:\Program Files\NVIDIA Corporation\nTune\NVMonitor.exe
C:\Program Files\PokerStove\PokerStove.exe
C:\Program Files\PokerStars\PokerStars.exe
C:\Program Files\PokerAce Hud\PAHud.exe
C:\Program Files\PokerAce Hud\PAHud.exe
C:\Program Files\PokerTracker 3\PokerTracker.exe
C:\Program Files\PokerTracker 3\PokerTracker.exe
C:\Program Files\PokerTracker 3\PokerTrackerHud.exe
C:\WINDOWS\system32\PnkBstrB.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: Java(tm) Plug-In SSV Helper - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre6\bin\ssv.dll
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre6\bin\jusched.exe"
O4 - HKLM\..\Run: [CTxfiHlp] CTXFIHLP.EXE
O4 - HKLM\..\Run: [Launch LgDevAgt] "C:\Program Files\Logitech\GamePanel Software\LgDevAgt.exe"
O4 - HKLM\..\Run: [Launch LCDMon] "C:\Program Files\Logitech\GamePanel Software\LCD Manager\LCDMon.exe"
O4 - HKLM\..\Run: [Launch LGDCore] "C:\Program Files\Logitech\GamePanel Software\G-series Software\LGDCore.exe" /SHOWHIDE
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKCU\..\Run: [SpybotSD TeaTimer] C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
O4 - HKCU\..\Run: [NVIDIA nTune] "C:\Program Files\NVIDIA Corporation\nTune\nTuneCmd.exe" clear
O4 - HKCU\..\Run: [EA Core] "C:\Program Files\Electronic Arts\EADM\Core.exe" -silent
O9 - Extra button: PokerStars - {3AD14F0C-ED16-4e43-B6D8-661B03F6A1EF} - C:\Program Files\PokerStars\PokerStarsUpdate.exe
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: avast! Antivirus - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Web Scanner - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
O23 - Service: Creative Audio Engine Licensing Service - Creative Labs - C:\Program Files\Common Files\Creative Labs Shared\Service\CTAELicensing.exe
O23 - Service: Creative Audio Service (CTAudSvcService) - Creative Technology Ltd - C:\Program Files\Creative\Shared Files\CTAudSvc.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: IviRegMgr - InterVideo - C:\Program Files\Common Files\InterVideo\RegMgr\iviRegMgr.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Program Files\Java\jre6\bin\jqs.exe
O23 - Service: LexBce Server (LexBceS) - Lexmark International, Inc. - C:\WINDOWS\system32\LEXBCES.EXE
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: PostgreSQL Database Server 8.3 (pgsql-8.3) - PostgreSQL Global Development Group - C:\Program Files\PostgreSQL\8.3\bin\pg_ctl.exe
O23 - Service: PnkBstrA - Unknown owner - C:\WINDOWS\system32\PnkBstrA.exe
O23 - Service: PnkBstrB - Unknown owner - C:\WINDOWS\system32\PnkBstrB.exe

--
End of file - 5564 bytes

I'm sure there was a thread on this a while back... can't find it in the search though

Searched this forum for anything with "noise" in it and the only comparable thread was about someone with a door opening and shutting sound, which I recognized as probably an IM sound before reading the responses and I don't use any IM software. I also always wear headphones, so this isn't some perv hiding out in my room in case that's a suggested possibility

Is it a banner ad somewhere? See this thread for an example of someone who seemed to have the same problem as you on an OSX installation.

Nope, happens when Firefox is closed. It also doesn't sound exactly like a camera flash. It'll make a click and then a flash type sound a second later. Doesn't sound exactly like a flash camera but close, and not very high quality (i.e., not a clear and decent immitation of a camera sound).

EDIT: also noscript does a pretty good job of blocking ads.

Fair enough.

Is it definitely not hardware related? Does it happen only when your speakers are turned on?

You badly need to update Internet Explorer to version 7, by the way. That's not running a tight ship. Even if you use Firefox as your web browser, having an old/unpatched installation of IE is a vulnerability (and IE is often called upon by other applications).

Have you had a folder open where you've done a search? The animated search 'characters' (dog, paperclip) have sounds they make from time to time when a folder is open where they were activated.

that's it imo

This is probably the culprit. I rarely ever do this and I just happened to have a search window and the folder I was searching in opened over the last couple days (hand history folder looking for something). I hadn't heard anything today after restarting last night, so I tried the above and the noise came back. Thanks

I had a similar problem once. Tried all the troubleshooting and everything. Turns out, it was a pretty bad undetected case of narcissism. Therapy's been going pretty well. ... I'm not allowed to look at cameras in wal mart any more though :/

No wonder you're in therapy. It's OK to look at cameras. It's just NOT OK for them to look at you! Jeez, the American Indians had this figured out over a century ago.

---------------Kitty

Jeez.. I've been trying to figure out the source of this randomly playing mystery sound forever! It happened on my old Windows XP laptop and I dug deep for a virus or trojan but came up clean, then it started happening on my Windows XP x64 desktop as well. I went so far as to listen to every sound file on my computer, and still couldn't locate it. I was sure it was coming from a program or WAV.. definitely from the speakers--not a hardware issue.

You are 100% right on the source. It's the f'n search dog. I guess that explains why it hasn't happened on my Vista machine. The sound happens when he does the scratch animation (which does appear to be at random intervals). It's 2 scratches, one right after the other, the playtime is about 2 seconds long and the second scratch sound is a little more muted than the first and trails off. I had also searched for chirp, picture, camera, photo, crumple, paper, recycle. (for the benefit of other people searching on this issue, I'm keyword loading)

Anyway, thanks so much for the answer. I can sleep soundly now

Go to Start --> Search, do a search for *.wav files on your local hard drive. Include hidden files and folders. When the list comes up, look for a file that describes what you're hearing, like camera.wav, shutter.wav, click.wav, something like that. Right click on that file and play it to be sure that's what you're hearing. When you locate it, look to see where it is; that will tell you what program is using it. Open that program, go to Options, Settings, or whatever, and turn off the sound or sounds. My 'camera' sound was coming from my desktop weather software.