Besoin d'aide d'analyse du rapport Hijackthi

Bonjour,
J'ai un problème de blocage du PC et parfois d'arrêt ,j'aurai besoin de votre aide pour l'analyse du rapport Hijackthis suivant et merci infiniment.
Logfile of HijackThis v1.99.1
Scan saved at 14:38:51, on 15-10-2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16544)

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:\WINDOWS\system32\ZoneLabs\vsmon.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
C:\WINDOWS\system32\inetsrv\inetinfo.exe
C:\WINDOWS\System32\snmp.exe
C:\Program Files\Analog Devices\SoundMAX\SMAgent.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\mqsvc.exe
C:\WINDOWS\system32\mqtgsvc.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\tsnpstd3.exe
C:\WINDOWS\vsnpstd3.exe
C:\Program Files\Analog Devices\SoundMAX\SMTray.exe
C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe
C:\Program Files\Java\jre1.6.0_03\bin\jusched.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\SAGEM\SAGEM F@st 800-840\dslmon.exe
C:\Program Files\Orbitdownloader\orbitdm.exe
C:\Program Files\Orbitdownloader\orbitnet.exe
C:\PROGRA~1\ZONELA~1\ZONEAL~1\MAILFR~1\mantispm.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\Program Files\Real\RealPlayer\RealPlay.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Documents and Settings\firenet\Mes documents\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://search.yahoo.com/?fr=altavista
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
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://www.google.fr/toolbar/ie8/sidebar.html
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page =
R1 - HKCU\Software\Microsoft\Internet Connection Wizard,ShellNext = http://runonce.msn.com/runonce3.aspx
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: btorbit.com - {000123B4-9B42-4900-B3F7-F4B073EFC214} - C:\Program Files\Orbitdownloader\orbitcth.dll
O2 - BHO: Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 5.0\Reader\ActiveX\AcroIEHelper.ocx
O2 - BHO: RealPlayer Download and Record Plugin for Internet Explorer - {3049C3E9-B461-4BC5-8870-4C09146192CA} - C:\Program Files\Real\RealPlayer\rpbrowserrecordplugin.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0_03\bin\ssv.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: Yahoo! Toolbar avec bloqueur de fenêtres pop-up - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O4 - HKLM\..\Run: [tsnpstd3] C:\WINDOWS\tsnpstd3.exe
O4 - HKLM\..\Run: [snpstd3] C:\WINDOWS\vsnpstd3.exe
O4 - HKLM\..\Run: [Smapp] C:\Program Files\Analog Devices\SoundMAX\SMTray.exe
O4 - HKLM\..\Run: [SetRefresh] "C:\Program Files\Compaq\SetRefresh\SetRefresh.exe"
O4 - HKLM\..\Run: [MsmqIntCert] regsvr32 /s mqrt.dll
O4 - HKLM\..\Run: [LayoutM] KLayMgr.exe
O4 - HKLM\..\Run: [TkBellExe] "C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [ZoneAlarm Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_03\bin\jusched.exe"
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - Global Startup: DSLMON.lnk = ?
O4 - Global Startup: Orbit.lnk = C:\Program Files\Orbitdownloader\orbitdm.exe
O8 - Extra context menu item: &Download by Orbit - res://C:\Program Files\Orbitdownloader\orbitmxt.dll/201
O8 - Extra context menu item: &Grab video by Orbit - res://C:\Program Files\Orbitdownloader\orbitmxt.dll/204
O8 - Extra context menu item: Ajouter à Kaspersky Anti-Bannière - C:\Program Files\Kaspersky Lab\Kaspersky Internet Security 7.0\ie_banner_deny.htm
O8 - Extra context menu item: Do&wnload selected by Orbit - res://C:\Program Files\Orbitdownloader\orbitmxt.dll/203
O8 - Extra context menu item: Down&load all by Orbit - res://C:\Program Files\Orbitdownloader\orbitmxt.dll/202
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_03\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_03\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: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\WINDOWS\system32\shdocvw.dll
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\WINDOWS\system32\shdocvw.dll
O11 - Options group: [INTERNATIONAL] International*
O16 - DPF: {30528230-99f7-4bb4-88d8-fa1d4f56a2ab} (YInstStarter Class) - C:\Program Files\Yahoo!\Common\yinsthelper.dll
O16 - DPF: {5D86DDB5-BDF9-441B-9E9E-D4730F4EE499} (BDSCANONLINE Control) - http://download.bitdefender.com/resources/scan8/oscan8.cab
O16 - DPF: {6E32070A-766D-4EE6-879C-DC1FA91D2FC3} (MUWebControl Class) - http://www.update.microsoft.com/...
O16 - DPF: {BB21F850-63F4-4EC9-BF9D-565BD30C9AE9} (a-squared Scanner) - http://ax.emsisoft.com/asquared.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
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 - Unknown owner - 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: AVG Anti-Spyware Guard - GRISOFT s.r.o. - C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: HP WMI Interface (hpqwmi) - Hewlett-Packard Development Company, L.P. - C:\Program Files\HPQ\Shared\hpqwmi.exe
O23 - Service: SoundMAX Agent Service (SoundMAX Agent Service (default)) - Analog Devices, Inc. - C:\Program Files\Analog Devices\SoundMAX\SMAgent.exe
O23 - Service: TrueVector Internet Monitor (vsmon) - Zone Labs, LLC - C:\WINDOWS\system32\ZoneLabs\vsmon.exe