PC qui rame surtout sur internet

Bonjour,
J'ai un pc portable qui rame de plus en plus. Particulièrement en me connectant sur internet. De plus la connection se coupe régulièrement pendant quelques secondes ce qui ne facilite pas les choses.
Avant j'utilisais Mozilla, depuis peu Google Chrome qi est un peu plus rapide.
Mais c'est toujours lent, ça bugg, bref, mon pc n'est pas vieux j'aimerai que ça tourne!!!
J'ai récemment suivi les instructions d'autres post, à savoir un scan et un nettoyage complet avec Ccleaner, Malwarebytes, Spybot et avast, mon pare feu. J'ai aussi défragmenté les disques mais il n'y a qu'une légère amélioration, pas de quoi sauter au plafond.
Donc là j'ai fait un Hijack, car j'espère que quelqu'un ici pourra m'aider.
Voici le rapport:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 09:57:08, on 23/06/2009
Platform: Windows Vista (WinNT 6.00.1904)
MSIE: Internet Explorer v7.00 (7.00.6000.16851)
Boot mode: Normal

Running processes:
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Windows\system32\taskeng.exe
C:\Program Files\Alwil Software\Avast4\ashDisp.exe
C:\Program Files\iTunes\iTunesHelper.exe
C:\Program Files\Yahoo!\Messenger\ymsgr_tray.exe
C:\Program Files\Windows Live\Messenger\msnmsgr.exe
C:\Program Files\Windows Media Player\wmpnscfg.exe
C:\Program Files\Windows Live\Contacts\wlcomm.exe
C:\Users\Marie\Documents\Downloads\HiJackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://fr.rd.yahoo.com/customize/ie/defaults/sp/msgr9/*https://fr.search.yahoo.com/
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://fr.yahoo.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = https://fr.yahoo.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://fr.rd.yahoo.com/customize/ie/defaults/su/msgr9/*https://fr.search.yahoo.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://fr.rd.yahoo.com/customize/ie/defaults/sp/msgr9/*https://fr.search.yahoo.com/
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = https://fr.yahoo.com/
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://fr.rd.yahoo.com/customize/ie/defaults/su/msgr9/*https://fr.search.yahoo.com/
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
R3 - URLSearchHook: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\PROGRA~1\Yahoo!\Companion\Installs\cpn\yt.dll
O1 - Hosts: ::1 localhost
O2 - BHO: &Yahoo! Toolbar Helper - {02478D38-C3F9-4efb-9B51-7695ECA05670} - C:\PROGRA~1\Yahoo!\Companion\Installs\cpn\yt.dll
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: Java(tm) Plug-In SSV Helper - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre6\bin\ssv.dll
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
O2 - BHO: SingleInstance Class - {FDAD4DA1-61A2-4FD8-9C17-86F7AC245081} - C:\PROGRA~1\Yahoo!\Companion\Installs\cpn\YTSingleInstance.dll
O3 - Toolbar: (no name) - {32099AAC-C132-4136-9E9A-4E364A424E17} - (no file)
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\PROGRA~1\Yahoo!\Companion\Installs\cpn\yt.dll
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 8.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKCU\..\Run: [Messenger (Yahoo!)] "C:\Program Files\Yahoo!\Messenger\YahooMessenger.exe" -quiet
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')
O8 - Extra context menu item: Add to Google Photos Screensa&ver - res://C:\Windows\system32\GPhotos.scr/200
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\Office12\REFIEBAR.DLL
O9 - Extra button: Run IMVU - {d9288080-1baa-4bc4-9cf8-a92d743db949} - C:\Users\Marie\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\IMVU\Run IMVU.lnk (file missing)
O13 - Gopher Prefix:
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.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! Mail Scanner - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
O23 - Service: avast! Web Scanner - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashWebSv.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: FLEXnet Licensing Service - Macrovision Europe Ltd. - C:\Program Files\Common Files\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: Service de l’iPod (iPod Service) - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: IviRegMgr - InterVideo - c:\Program Files\Common Files\InterVideo\RegMgr\iviRegMgr.exe
O23 - Service: lxbk_device - - C:\Windows\system32\lxbkcoms.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Program Files\CyberLink\Shared Files\RichVideo.exe
O23 - Service: SBSD Security Center Service (SBSDWSCService) - Safer Networking Ltd. - C:\Program Files\Spybot - Search & Destroy\SDWinSec.exe
O23 - Service: ServiceLayer - Nokia. - C:\Program Files\PC Connectivity Solution\ServiceLayer.exe
O23 - Service: Fujitsu Siemens Computers Diagnostic Testhandler (TestHandler) - Fujitsu Siemens Computers - C:\firststeps\OnlineDiagnostic\TestManager\TestHandler.exe
O23 - Service: CLCV0 (UTSCSI) - Unknown owner - C:\Windows\system32\UTSCSI.EXE
O23 - Service: XAudioService - Conexant Systems, Inc. - C:\Windows\system32\DRIVERS\xaudio.exe
O23 - Service: Yahoo! Updater (YahooAUService) - Yahoo! Inc. - C:\Program Files\Yahoo!\SoftwareUpdate\YahooAUService.exe