PC qui travaille tout seul et tout le temps

Bonjour,

Depuis quelques temps mon PC se met à travailler tout seul, la diode rouge qui s'allume quand il y a écriture sur le disque dur ou un autre travail de l'ordinateur, reste allumée tout le temps ou presque, et j'entends comme si ça écrivait.
J'ai fait une analyse HiJackThis de laquelle j'en tire le rapport suivant :

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 14:49:13, on 13/06/2010
Platform: Windows Vista SP2 (WinNT 6.00.1906)
MSIE: Internet Explorer v8.00 (8.00.6001.18928)
Boot mode: Normal

Running processes:
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Program Files\Windows Defender\MSASCui.exe
C:\Windows\RtHDVCpl.exe
C:\Windows\System32\SysMonitor.exe
C:\Windows\system32\taskeng.exe
C:\Program Files\Common Files\Symantec Shared\PIF\{B8E1DD85-8582-4c61-B58F-2F227FCA9A08}\PIFSvc.exe
C:\Windows\System32\rundll32.exe
C:\Windows\System32\M-AudioTaskBarIcon.exe
C:\Program Files\Common Files\Java\Java Update\jusched.exe
C:\Program Files\Adobe\Reader 8.0\Reader\reader_sl.exe
C:\Windows\System32\LVCOMSX.EXE
C:\Program Files\Alwil Software\Avast5\AvastUI.exe
C:\Program Files\Windows Sidebar\sidebar.exe
C:\Windows\ehome\ehtray.exe
C:\Program Files\Windows Media Player\wmpnscfg.exe
C:\Program Files\Windows Media Player\wmplayer.exe
C:\Windows\system32\wbem\unsecapp.exe
C:\Windows\ehome\ehmsas.exe
C:\Program Files\Internet Explorer\IELowutil.exe
C:\Program Files\trend micro\hijackthis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://go.microsoft.com/fwlink/?linkid=54896
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.msn.com/fr-fr
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.msn.com/fr-fr
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
O1 - Hosts: ::1 localhost
O2 - BHO: Aide pour le lien d'Adobe PDF Reader - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {5C255C8A-E604-49b4-9D64-90988571CECB} - (no file)
O2 - BHO: Programme d'aide de l'Assistant de connexion Windows Live - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre6\bin\jp2ssv.dll
O3 - Toolbar: Acer eDataSecurity Management - {5CBE3B7C-1E47-477e-A7DD-396DB0476E29} - C:\Windows\system32\eDStoolbar.dll
O4 - HKLM\..\Run: [Windows Defender] %ProgramFiles%\Windows Defender\MSASCui.exe -hide
O4 - HKLM\..\Run: [RtHDVCpl] RtHDVCpl.exe
O4 - HKLM\..\Run: [Acer Empowering Technology Monitor] C:\Windows\system32\SysMonitor.exe
O4 - HKLM\..\Run: [WarReg_PopUp] C:\Acer\WR_PopUp\WarReg_PopUp.exe
O4 - HKLM\..\Run: [eDataSecurity Loader] C:\Acer\Empowering Technology\eDataSecurity\eDSloader.exe
O4 - HKLM\..\Run: [NeroFilterCheck] C:\Windows\system32\NeroCheck.exe
O4 - HKLM\..\Run: [NBKeyScan] "C:\Program Files\Nero\Nero8\Nero BackItUp\NBKeyScan.exe"
O4 - HKLM\..\Run: [Symantec PIF AlertEng] "C:\Program Files\Common Files\Symantec Shared\PIF\{B8E1DD85-8582-4c61-B58F-2F227FCA9A08}\PIFSvc.exe" /a /m "C:\Program Files\Common Files\Symantec Shared\PIF\{B8E1DD85-8582-4c61-B58F-2F227FCA9A08}\AlertEng.dll"
O4 - HKLM\..\Run: [ORAHSSSessionManager] "C:\Program Files\OrangeHSS\SessionManager\SessionManager.exe"
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\Windows\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\Windows\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [M-Audio Taskbar Icon] C:\Windows\System32\M-AudioTaskBarIcon.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Common Files\Java\Java Update\jusched.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 8.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [Adobe ARM] "C:\Program Files\Common Files\Adobe\ARM\1.0\AdobeARM.exe"
O4 - HKLM\..\Run: [LVCOMSX] C:\Windows\system32\LVCOMSX.EXE
O4 - HKLM\..\Run: [CamWizard] C:\Program Files\Common Files\Logitech\QCDRV\BIN\CamWizrd.exe
O4 - HKLM\..\Run: [LogitechVideoRepair] C:\Program Files\Logitech\Video\ISStart.exe /RegAll
O4 - HKLM\..\Run: [LogitechVideoTray] C:\Program Files\Logitech\Video\LogiTray.exe
O4 - HKLM\..\Run: [avast5] C:\PROGRA~1\ALWILS~1\Avast5\avastUI.exe /nogui
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\QTTask.exe" -atboottime
O4 - HKCU\..\Run: [Sidebar] C:\Program Files\Windows Sidebar\sidebar.exe /autoRun
O4 - HKCU\..\Run: [ehTray.exe] C:\Windows\ehome\ehTray.exe
O4 - HKCU\..\Run: [ISUSPM Startup] "C:\Program Files\Common Files\InstallShield\UpdateService\ISUSPM.exe" -startup
O4 - HKCU\..\Run: [Google Update] "C:\Users\Tito\AppData\Local\Google\Update\GoogleUpdate.exe" /c
O4 - HKCU\..\Run: [LogitechSoftwareUpdate] "C:\Program Files\Logitech\Video\ManifestEngine.exe" boot
O4 - HKCU\..\Run: [WMPNSCFG] C:\Program Files\Windows Media Player\WMPNSCFG.exe
O4 - HKCU\..\Run: [ccleaner] "C:\Program Files\CCleaner\CCleaner.exe" /AUTO
O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /detectMem (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-19\..\Run: [WindowsWelcomeCenter] rundll32.exe oobefldr.dll,ShowWelcomeCenter (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /detectMem (User 'SERVICE RÉSEAU')
O4 - Global Startup: Empowering Technology Launcher.lnk = ?
O13 - Gopher Prefix:
O16 - DPF: {C3F79A2B-B9B4-4A66-B012-3EE46475B072} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsPAClient.cab56907.cab
O23 - Service: ePerformance Service (AcerMemUsageCheckService) - Unknown owner - C:\Acer\Empowering Technology\ePerformance\MemCheck.exe
O23 - Service: Apple Mobile Device - Apple, Inc. - C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
O23 - Service: avast! Antivirus - ALWIL Software - C:\Program Files\Alwil Software\Avast5\AvastSvc.exe
O23 - Service: avast! Mail Scanner - ALWIL Software - C:\Program Files\Alwil Software\Avast5\AvastSvc.exe
O23 - Service: avast! Web Scanner - ALWIL Software - C:\Program Files\Alwil Software\Avast5\AvastSvc.exe
O23 - Service: Service Bonjour (Bonjour Service) - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: Symantec Lic NetConnect service (CLTNetCnService) - Unknown owner - c:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe (file missing)
O23 - Service: eRecovery Service (eRecoveryService) - Acer Inc. - C:\Acer\Empowering Technology\eRecovery\eRecoveryService.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - C:\Program Files\Common Files\LightScribe\LSSrvc.exe
O23 - Service: LiveUpdate - Symantec Corporation - C:\PROGRA~1\Symantec\LIVEUP~1\LUCOMS~1.EXE
O23 - Service: LiveUpdate Notice Service Ex (LiveUpdate Notice Ex) - Unknown owner - c:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe (file missing)
O23 - Service: LiveUpdate Notice Service - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\PIF\{B8E1DD85-8582-4c61-B58F-2F227FCA9A08}\PIFSvc.exe
O23 - Service: M-Audio KeyStudio 49i Installer (MAudioKeyStudio49iService) - Unknown owner - C:\Program Files\M-Audio\KeyStudio 49i\MAUSBKeyStudio49iInst.exe (file missing)
O23 - Service: Nero BackItUp Scheduler 3 - Nero AG - C:\Program Files\Nero\Nero8\Nero BackItUp\NBService.exe
O23 - Service: NMIndexingService - Nero AG - C:\Program Files\Common Files\Nero\Lib\NMIndexingService.exe
O23 - Service: NVIDIA Display Driver Service (nvsvc) - NVIDIA Corporation - C:\Windows\system32\nvvsvc.exe
O23 - Service: Planificateur LiveUpdate automatique - Symantec Corporation - C:\Program Files\Symantec\LiveUpdate\ALUSchedulerSvc.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Program Files\CyberLink\Shared Files\RichVideo.exe