Internet ne marche pas

bonjour,
je vous écris vis à vis d'un problème rencontré lors de la connexion internet ce qui se passe c'est que explorer ouvre certaines pages mais certaine pages ne s'ouvrent pas et j'ai le message "impossible d'afficher la page" j'ai fait un test ping ya qqes minutes et il marque une perte de 2 dossiers sur 4 donc 50% je ne sais pas comment faire....
J'ai mêm fait un scan hijackthis et ça m'affiche ce log en dessous
Logfile of HijackThis v1.99.1
Scan saved at 04:26:15, on 01/09/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16512)

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\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\ehome\ehtray.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\Program Files\InterVideo\Common\Bin\WinCinemaMgr.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe
C:\WINDOWS\eHome\ehRecvr.exe
C:\Program Files\MSN Messenger\MsnMsgr.Exe
C:\WINDOWS\eHome\ehSched.exe
C:\WINDOWS\system32\ctfmon.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Norman\Bin\Zanda.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\Program Files\Norman\Nvc\BIN\NVCSCHED.EXE
C:\Program Files\Norman\Nvc\BIN\nipsvc.exe
C:\Program Files\Norman\bin\NJEEVES.EXE
C:\WINDOWS\eHome\ehmsas.exe
C:\WINDOWS\system32\dllhost.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Hijackthis Version Française\VERSION TRADUITE ORIGINALE.EXE

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = https://www.bing.com/?cc=fr&toHttps=1&redig=55729C844D6A45819CAD368B3E178C9F
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
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Fichiers communs\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: RealPlayer Download and Record Plugin for Internet Explorer - {3049C3E9-B461-4BC5-8870-4C09146192CA} - C:\Program Files\Real\RealPlayer\rpbrowserrecordplugin.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Fichiers communs\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O3 - Toolbar: Barre d'outils MSN - {BDAD1DAD-C946-4A17-ADC1-64B5B4FF55D0} - C:\Program Files\MSN Toolbar\01.01.2607.0\fr\msntb.dll
O4 - HKLM\..\Run: [ehTray] C:\WINDOWS\ehome\ehtray.exe
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [Recguard] C:\WINDOWS\SMINST\RECGUARD.EXE
O4 - HKLM\..\Run: [WINCINEMAMGR] "C:\Program Files\InterVideo\Common\Bin\WinCinemaMgr.exe"
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: [TkBellExe] "C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\jre1.5.0_03\bin\jusched.exe
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files\MSN Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - Global Startup: InterVideo WinCinema Manager.lnk = C:\Program Files\InterVideo\Common\Bin\WinCinemaMgr.exe
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_03\bin\npjpi150_03.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_03\bin\npjpi150_03.dll
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: 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
O11 - Options group: [INTERNATIONAL] International*
O16 - DPF: {8AD9C840-044E-11D1-B3E9-00805F499D93} (Java Runtime Environment 1.5.0) - http://javadl-esd.sun.com/update/1.5.0/jinstall-1_5_0_03-windows-i586.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: Ati HotKey Poller - ATI Technologies Inc. - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: avast! Antivirus - ALWIL Software - 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: Norman API-hooking helper (NipSvc) - Unknown owner - C:\Program Files\Norman\Nvc\BIN\nipsvc.exe
O23 - Service: Norman NJeeves - Unknown owner - C:\Program Files\Norman\bin\NJEEVES.EXE
O23 - Service: Norman ZANDA - Unknown owner - C:\Program Files\Norman\Bin\Zanda.exe
O23 - Service: Norman Virus Control on-access component (nvcoas) - Norman ASA - C:\Program Files\Norman\Nvc\bin\nvcoas.exe
O23 - Service: Norman Virus Control Scheduler (NVCScheduler) - Norman Data Defense Systems - C:\Program Files\Norman\Nvc\BIN\NVCSCHED.EXE

pour moi c'est du charabien aidez moi svp...