J'ai des pop up qui s'ouvrent régulièrement, avant c'était uniquement avec IE7 et maintenant avec Firefox 2 aussi.
Voici le rapport Hijackjthis, merci pour votre aide.

Logfile of HijackThis v1.99.1
Scan saved at 12:18:32, on 11/03/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16414)

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:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Java\jre1.5.0_11\bin\jusched.exe
C:\PROGRA~1\LEXMAR~1\ACMonitor_X83.exe
C:\PROGRA~1\LEXMAR~1\AcBtnMgr_X83.exe
C:\WINDOWS\System32\M-AudioTaskBarIcon.exe
C:\WINDOWS\system32\RUNDLL32.EXE
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Logitech\SetPoint\SetPoint.exe
C:\Program Files\PVR Series\Watch.exe
C:\Program Files\PVR Series\Watch.exe
C:\WINDOWS\system32\rundll32.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\PROGRA~1\Wanadoo\TaskBarIcon.exe
C:\Program Files\Fichiers communs\Logitech\KHAL\KHALMNPR.EXE
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\PROGRA~1\Wanadoo\GestionnaireInternet.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
C:\WINDOWS\System32\FTRTSVC.exe
C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
C:\PROGRA~1\Wanadoo\ComComp.exe
C:\Program Files\M-Audio\Fast Track Pro\MAUSBInst.exe
C:\PROGRA~1\Wanadoo\Toaster.exe
C:\PROGRA~1\Wanadoo\Inactivity.exe
C:\PROGRA~1\Wanadoo\PollingModule.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\system32\RioMSC.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\ALERTM~1\ALERTM~1.EXE
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\PROGRA~1\Wanadoo\Watch.exe
C:\Program Files\Mozilla Thunderbird\thunderbird.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\Google\Google Talk\googletalk.exe
D:\divers\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.google.fr/ig?hl=fr
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Orange
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
R3 - URLSearchHook: Search Class - {08C06D61-F1F3-4799-86F8-BE1A89362C85} - C:\PROGRA~1\Wanadoo\SEARCH~1.DLL
R3 - URLSearchHook: Torrent-Search Toolbar - {e0c7b854-d5ce-4db6-9804-be1438603d89} - C:\Program Files\Torrent-Search\tbTorr.dll
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.5.0_11\bin\ssv.dll
O2 - BHO: FoxyTunes Toolbar Helper - {784D8FBC-4165-4D88-90FB-62907ACDD045} - C:\Program Files\FoxyTunes\ForInternetExplorer\components\IE\FoxyTunesForIE.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Fichiers communs\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - c:\program files\google\googletoolbar2.dll
O2 - BHO: Torrent-Search Toolbar - {e0c7b854-d5ce-4db6-9804-be1438603d89} - C:\Program Files\Torrent-Search\tbTorr.dll
O3 - Toolbar: Yahoo! Toolbar avec bloqueur de fenêtres pop-up - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O3 - Toolbar: FoxyTunes Toolbar - {1D1901C3-F72A-46f3-9DBB-0AAA0DEEF6DF} - C:\Program Files\FoxyTunes\ForInternetExplorer\components\IE\FoxyTunesForIE.dll
O3 - Toolbar: Torrent-Search Toolbar - {e0c7b854-d5ce-4db6-9804-be1438603d89} - C:\Program Files\Torrent-Search\tbTorr.dll
O3 - Toolbar: &Google - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - c:\program files\google\googletoolbar2.dll
O4 - HKLM\..\Run: [Logitech Hardware Abstraction Layer] KHALMNPR.EXE
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [Google Desktop Search] "C:\Program Files\Google\Google Desktop Search\GoogleDesktop.exe" /startup
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.5.0_11\bin\jusched.exe"
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [Lexmark X83 Button Monitor] C:\PROGRA~1\LEXMAR~1\ACMonitor_X83.exe
O4 - HKLM\..\Run: [Lexmark X83 Button Manager] C:\PROGRA~1\LEXMAR~1\AcBtnMgr_X83.exe
O4 - HKLM\..\Run: [TkBellExe] "C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [M-Audio Taskbar Icon] C:\WINDOWS\System32\M-AudioTaskBarIcon.exe
O4 - HKLM\..\Run: [WOOWATCH] C:\PROGRA~1\Wanadoo\Watch.exe
O4 - HKLM\..\Run: [WOOTASKBARICON] C:\PROGRA~1\Wanadoo\GestMaj.exe TaskBarIcon.exe
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [googletalk] C:\Program Files\Google\Google Talk\googletalk.exe /autostart
O4 - HKLM\..\Run: [{0228e555-4f9c-4e35-a3ec-b109a192b4c2}] C:\Program Files\Google\Gmail Notifier\gnotify.exe
O4 - HKLM\..\Run: [Zone Labs Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKCU\..\Run: [WOOKIT] C:\PROGRA~1\Wanadoo\Shell.exe appLaunchClientZone.shl|PARAM= cnx
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [Skype] "C:\Program Files\Skype\Phone\Skype.exe" /nosplash /minimized
O4 - Startup: Adobe Gamma.lnk = C:\Program Files\Fichiers communs\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Startup: PowerReg Scheduler.exe
O4 - Startup: Watch.lnk = C:\Program Files\PVR Series\Watch.exe
O4 - Global Startup: Google Updater.lnk = C:\Program Files\Google\Google Updater\GoogleUpdater.exe
O4 - Global Startup: Lancement rapide d'Adobe Reader.lnk = C:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Logitech SetPoint.lnk = C:\Program Files\Logitech\SetPoint\SetPoint.exe
O4 - Global Startup: Watch.lnk = C:\Program Files\PVR Series\Watch.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
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_11\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_11\bin\ssv.dll
O9 - Extra button: (no name) - {85d1f590-48f4-11d9-9669-0800200c9a66} - %windir%\bdoscandel.exe (file missing)
O9 - Extra 'Tools' menuitem: Uninstall BitDefender Online Scanner v8 - {85d1f590-48f4-11d9-9669-0800200c9a66} - %windir%\bdoscandel.exe (file missing)
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra button: Orange - {1462651F-F4BA-4C76-A001-C4284D0FE16E} - http://www.orange.fr (file missing) (HKCU)
O11 - Options group: [INTERNATIONAL] International*
O12 - Plugin for .spop: C:\Program Files\Internet Explorer\Plugins\NPDocBox.dll
O16 - DPF: {0EB0E74A-2A76-4AB3-A7FB-9BD8C29F7F75} (CKAVWebScan Object) - http://webscanner.kaspersky.fr/kavwebscan_unicode.cab
O16 - DPF: {474F00F5-3853-492C-AC3A-476512BBC336} (UploadListView Class) - http://picasaweb.google.com/s/v/14.22/uploader2.cab
O16 - DPF: {5D86DDB5-BDF9-441B-9E9E-D4730F4EE499} (BDSCANONLINE Control) - http://download.bitdefender.com/re [...] oscan8.cab
O16 - DPF: {74D05D43-3236-11D4-BDCD-00C04F9A3B61} (HouseCall Control) - http://a840.g.akamai.net/7/840/537 [...] scan53.cab
O16 - DPF: {9A9307A0-7DA4-4DAF-B042-5009F29E09E1} (ActiveScan Installer Class) - http://acs.pandasoftware.com/activ [...] asinst.cab
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: skype4com - {FFC8B962-9B40-4DFF-9458-1830C7DD7F5D} - C:\PROGRA~1\FICHIE~1\Skype\SKYPE4~1.DLL
O20 - AppInit_DLLs: C:\PROGRA~1\Google\GOOGLE~2\GOEC62~1.DLL
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll
O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll
O23 - Service: Adobe LM Service - Adobe Systems - C:\Program Files\Fichiers communs\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - Unknown owner - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: avast! Antivirus - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Mail Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe" /service (file missing)
O23 - Service: avast! Web Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashWebSv.exe" /service (file missing)
O23 - Service: AVG Anti-Spyware Guard - Anti-Malware Development a.s. - C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: France Telecom Routing Table Service (FTRTSVC) - France Telecom - C:\WINDOWS\System32\FTRTSVC.exe
O23 - Service: GoogleDesktopManager - Google - C:\Program Files\Google\Google Desktop Search\GoogleDesktopManager.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Fichiers communs\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: M-Audio USB Installer (MAudioUSBService) - M-Audio - C:\Program Files\M-Audio\Fast Track Pro\MAUSBInst.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: RadClock - Unknown owner - C:\WINDOWS\system32\RadClock.exe
O23 - Service: RIO Mass Storage C (RioMSC) - Digital Networks North America, Inc. - C:\WINDOWS\system32\RioMSC.exe
O23 - Service: TrueVector Internet Monitor (vsmon) - Zone Labs, LLC - C:\WINDOWS\system32\ZoneLabs\vsmon.exe