Mon PC ne réagit plus...

Merci de ta réponse rapide ! Pour l'instant çà marche, j'essaierai la 1ère solution quand çà bloquera !
Est-ce le rapport hijackthis te parle ?
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 21:55 Michèle, on 03/01/2009
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16762)
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:\Program Files\Windows Defender\MsMpEng.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Lavasoft\Ad-Aware\aawservice.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Orange\AntivirusFirewall\Common\FSM32.EXE
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Vista Start Menu\VistaStartMenu.exe
C:\Program Files\EuroThink\Agenda\agenda.exe
C:\Documents and Settings\Acer\Application Data\Microsoft\Live Search\Notification-LiveSearch.exe
C:\Program Files\Pense-bete\pb79f.exe
C:\Documents and Settings\Acer\Application Data\Microsoft\Live Search\Mise-a-jour-LiveSearch.exe
C:\WINDOWS\System32\dllhost.exe
C:\Program Files\Orange\AntivirusFirewall\Anti-Virus\fsgk32st.exe
C:\Program Files\Orange\AntivirusFirewall\Common\FSMA32.EXE
C:\Program Files\Orange\AntivirusFirewall\Anti-Virus\FSGK32.EXE
C:\WINDOWS\System32\FTRTSVC.exe
C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
C:\Program Files\Orange\AntivirusFirewall\Common\FSMB32.EXE
C:\Program Files\Fichiers communs\LightScribe\LSSrvc.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\system32\oodag.exe
C:\Program Files\Orange\AntivirusFirewall\Common\FCH32.EXE
C:\Program Files\Microsoft\Search Enhancement Pack\SeaPort\SeaPort.exe
C:\WINDOWS\System32\TUProgSt.exe
C:\WINDOWS\system32\SearchIndexer.exe
C:\Program Files\Orange\AntivirusFirewall\Common\FAMEH32.EXE
C:\Program Files\Orange\AntivirusFirewall\Anti-Virus\fsqh.exe
C:\Program Files\Orange\AntivirusFirewall\FSGUI\fsguidll.exe
C:\Program Files\Orange\AntivirusFirewall\FSAUA\program\fsaua.exe
C:\Program Files\Orange\AntivirusFirewall\Anti-Virus\fssm32.exe
C:\Program Files\Orange\AntivirusFirewall\FWES\Program\fsdfwd.exe
C:\Program Files\Orange\AntivirusFirewall\FSAUA\program\fsus.exe
C:\Program Files\Orange\AntivirusFirewall\Anti-Virus\fsav32.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\WINDOWS\system32\SearchProtocolHost.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.orange.fr/portail
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = https://www.msn.com/fr-fr/?ocid=iehp
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = https://www.bing.com/?toHttps=1&redig=5FC791212101479BAFBE1A679848B1AF
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = https://www.bing.com/?toHttps=1&redig=5FC791212101479BAFBE1A679848B1AF
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.msn.com/fr-fr/?ocid=iehp
R1 - HKLM\Software\Microsoft\Internet Explorer\Search,Default_Search_URL = http://toolbar.ask.com/toolbarv/askRedirect?o=101699&gct=&gc=1&q=
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://www.bing.com/spresults.aspx
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Wanadoo
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = localhost
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
R3 - URLSearchHook: (no name) - {AEEC3B59-CA98-4EBA-A140-57B94E283583} - C:\PROGRA~1\ORANGE~1\TOOLBA~3.DLL
R3 - URLSearchHook: Search Class - {08C06D61-F1F3-4799-86F8-BE1A89362C85} - C:\PROGRA~1\Wanadoo\SEARCH~1.DLL
R3 - URLSearchHook: Yahoo! Toolbar avec bloqueur de fenêtres pop-up - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
R3 - URLSearchHook: DefaultSearchHook Class - {C94E154B-1459-4A47-966B-4B843BEFC7DB} - C:\Program Files\AskSearch\bin\DefaultSearch.dll
O2 - BHO: Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O2 - BHO: Adobe PDF Link Helper - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Fichiers communs\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: AskBar BHO - {201f27d4-3704-41d6-89c1-aa35e39143ed} - C:\Program Files\AskBarDis\bar\bin\askBar.dll
O2 - BHO: flashget urlcatch - {2F364306-AA45-47B5-9F9D-39A8B94E7EF7} - C:\Program Files\FlashGet\jccatch.dll
O2 - BHO: AVG Safe Search - {3CA2F312-6F6E-4B53-A66E-4E65E497C8C0} - (no file)
O2 - BHO: Spybot-S&D IE Protection - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: Search Helper - {6EBF7485-159F-4bff-A14F-B9E3AAC4465B} - C:\Program Files\Microsoft\Search Enhancement Pack\Search Helper\SearchHelper.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0_07\bin\ssv.dll
O2 - BHO: Programme d'aide de l'Assistant de connexion Windows Live - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Fichiers communs\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Program Files\Google\GoogleToolbarNotifier\4.1.805.4472\swg.dll
O2 - BHO: Windows Live Toolbar Helper - {BDBD1DAD-C946-4A17-ADC1-64B5B4FF55D0} - C:\Program Files\Windows Live Toolbar\msntb.dll
O2 - BHO: FlashGet GetFlash Class - {F156768E-81EF-470C-9057-481BA8380DBA} - C:\Program Files\FlashGet\getflash.dll
O3 - Toolbar: barre d'outils Orange - {D3028143-6145-4318-99D3-3EDCE54A95A9} - C:\Program Files\Orange Toolbar FR\ToolbarContainer234.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: Foxit Toolbar - {3041d03e-fd4b-44e0-b742-2d9b88305f98} - C:\Program Files\AskBarDis\bar\bin\askBar.dll
O3 - Toolbar: Windows Live Toolbar - {BDAD1DAD-C946-4A17-ADC1-64B5B4FF55D0} - C:\Program Files\Windows Live Toolbar\msntb.dll
O4 - HKLM\..\Run: [F-Secure Manager] "C:\Program Files\Orange\AntivirusFirewall\Common\FSM32.EXE" /splash
O4 - HKLM\..\Run: [F-Secure TNB] "C:\Program Files\Orange\AntivirusFirewall\FSGUI\TNBUtil.exe" /CHECKALL /WAITFORSW
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [VistaStartMenu] "C:\Program Files\Vista Start Menu\VistaStartMenu.exe"
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-19\..\Run: [OrangePlayer] c:\program files\orange\media player\Media Player.exe /systray (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SERVICE RÉSEAU')
O4 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'Default user')
O4 - Startup: Outil de notification Live Search.lnk = C:\Documents and Settings\Acer\Application Data\Microsoft\Live Search\Notification-LiveSearch.exe
O4 - Startup: Pense-Bête 79f.lnk = C:\Program Files\Pense-bete\pb79f.exe
O4 - Global Startup: EuroThink Agenda.lnk = C:\Program Files\EuroThink\Agenda\agenda.exe
O8 - Extra context menu item: &Tout télécharger avec FlashGet - C:\Program Files\FlashGet\jc_all.htm
O8 - Extra context menu item: &Télécharger avec FlashGet - C:\Program Files\FlashGet\jc_link.htm
O8 - Extra context menu item: &Windows Live Search - res://C:\Program Files\Windows Live Toolbar\msntb.dll/search.htm
O8 - Extra context menu item: Add to Google Photos Screensa&ver - res://C:\WINDOWS\system32\GPhotos.scr/200
O8 - Extra context menu item: Add to Windows &Live Favorites - https://onedrive.live.com/?id=favorites
O8 - Extra context menu item: traduire la page - C:\DOCUME~1\Acer\LOCALS~1\Temp\cce9B7.html
O8 - Extra context menu item: traduire le texte sélectionné - C:\DOCUME~1\Acer\LOCALS~1\Temp\cce9B8.html
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_07\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_07\bin\ssv.dll
O9 - Extra button: Ajout Direct - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
O9 - Extra 'Tools' menuitem: &Ajout Direct dans Windows Live Writer - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
O9 - Extra button: Protection Internet Explorer - {300DB664-75B5-47c0-8B45-A44ACCF73C00} - C:\WINDOWS\System32\shdocvw.dll
O9 - Extra 'Tools' menuitem: Protection Internet Explorer... - {300DB664-75B5-47c0-8B45-A44ACCF73C00} - C:\WINDOWS\System32\shdocvw.dll
O9 - Extra button: (no name) - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe (file missing)
O9 - Extra 'Tools' menuitem: Uninstall BitDefender Online Scanner v8 - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe (file missing)
O9 - Extra button: FlashGet - {D6E814A0-E0C5-11d4-8D29-0050BA6940E3} - C:\Program Files\FlashGet\FlashGet.exe
O9 - Extra 'Tools' menuitem: FlashGet - {D6E814A0-E0C5-11d4-8D29-0050BA6940E3} - C:\Program Files\FlashGet\FlashGet.exe
O9 - Extra button: (no name) - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O9 - Extra 'Tools' menuitem: Spybot - Search & Destroy Configuration - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
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: Messager Wanadoo - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\PROGRA~1\WANADO~1\Wanadoo Messager.exe
O9 - Extra 'Tools' menuitem: Messager Wanadoo - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\PROGRA~1\WANADO~1\Wanadoo Messager.exe
O9 - Extra button: Wanadoo - {1462651F-F4BA-4C76-A001-C4284D0FE16E} - https://www.orange.fr/portail (file missing) (HKCU)
O14 - IERESET.INF: START_PAGE_URL=https://www.acer.com/worldwide/selection.html
O16 - DPF: {17492023-C23A-453E-A040-C7C580BBF700} (Windows Genuine Advantage Validation Tool) -
O16 - DPF: {9F1C11AA-197B-4942-BA54-47A8489BB47F} -
O16 - DPF: {BB21F850-63F4-4EC9-BF9D-565BD30C9AE9} (a-squared Scanner) - http://ax.emsisoft.com/asquared.cab
O18 - Protocol: skype4com - {FFC8B962-9B40-4DFF-9458-1830C7DD7F5D} - C:\PROGRA~1\FICHIE~1\Skype\SKYPE4~1.DLL
O23 - Service: Lavasoft Ad-Aware Service (aawservice) - Lavasoft - C:\Program Files\Lavasoft\Ad-Aware\aawservice.exe
O23 - Service: Boonty Games - BOONTY - C:\Program Files\Fichiers communs\BOONTY Shared\Service\Boonty.exe
O23 - Service: FSGKHS (F-Secure Gatekeeper Handler Starter) - F-Secure Corporation - C:\Program Files\Orange\AntivirusFirewall\Anti-Virus\fsgk32st.exe
O23 - Service: FLEXnet Licensing Service - Macrovision Europe Ltd. - C:\Program Files\Fichiers communs\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: F-Secure Automatic Update Agent (FSAUA) - F-Secure Corporation - C:\Program Files\Orange\AntivirusFirewall\FSAUA\program\fsaua.exe
O23 - Service: F-Secure Anti-Virus Firewall Daemon (FSDFWD) - F-Secure Corporation - C:\Program Files\Orange\AntivirusFirewall\FWES\Program\fsdfwd.exe
O23 - Service: F-Secure Management Agent (FSMA) - F-Secure Corporation - C:\Program Files\Orange\AntivirusFirewall\Common\FSMA32.EXE
O23 - Service: France Telecom Routing Table Service (FTRTSVC) - France Telecom - C:\WINDOWS\System32\FTRTSVC.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: Logitech Bluetooth Service (LBTServ) - Logitech, Inc. - C:\Program Files\Fichiers communs\Logitech\Bluetooth\LBTServ.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - C:\Program Files\Fichiers communs\LightScribe\LSSrvc.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: O&O Defrag - O&O Software GmbH - C:\WINDOWS\system32\oodag.exe
O23 - Service: SiSoftware Deployment Agent Service (SandraAgentSrv) - SiSoftware - C:\Program Files\SiSoftware\SiSoftware Sandra Lite 2009.SP1b\RpcAgentSrv.exe
O23 - Service: TuneUp Drive Defrag Service (TuneUp.Defrag) - TuneUp Software - C:\WINDOWS\System32\TuneUpDefragService.exe
O23 - Service: TuneUp Program Statistics Service (TuneUp.ProgramStatisticsSvc) - TuneUp Software - C:\WINDOWS\System32\TUProgSt.exe

J'ai collé les logs dans hijackthis ; il y a en effet quelques saletés à virer ! Je te remercie d'avoir pris du temps pour m'aider, c'est sympa ! Quant à msconfig, bien sûr que je connais ; j'irai faire un tour pour arrêter quelques trucs !!!
Encore merci, j'espère que ce n'est pas plus grave et que je n'aurai plus mes problèmes. Bonne nuit.