Erreurs explorer.exe

Bonjour,
Je suis actuellement étudiant dans une formation à distance donc j'ai besoin de mon pc tous les jours hors j'ai de grâves problèmes que je n'arrive pas à résoudre. Je suis sous windows xp pro et quand je démarre mon ordinateur explorer ne se lance pas. Je dois alors passer par le gestionnaire des tâches pour le relancer mais alors la autre problème... toutes les 5 ou 6 secondes explorer bug et mon bureau redisparaît pour réapparaitres quelques secondes plus tard et ainsi de suite. Je vous poste ci-dessous un log de scan hijackthis.

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 21:08:54, on 19/10/2008
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16735)
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:\WINDOWS\System32\svchost.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\RUNDLL32.EXE
C:\Program Files\NVIDIA Corporation\NvMixer\NVMixerTray.exe
C:\Program Files\Java\jre1.6.0_07\bin\jusched.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\MSN Messenger\MsnMsgr.Exe
C:\program files\steam\steam.exe
C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
C:\Program Files\Bonjour\mDNSResponder.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\Program Files\MSN Messenger\usnsvc.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\Spybot - Search & Destroy\SpybotSD.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.google.fr/?gws_rd=ssl
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
O3 - Toolbar: VMN Toolbar - {4E7BD74F-2B8D-469E-8DA9-FD60BB9AAE33} - C:\PROGRA~1\VMNTOO~1\VMNTOO~1.DLL
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [NVMixerTray] "C:\Program Files\NVIDIA Corporation\NvMixer\NVMixerTray.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 9.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [KernelFaultCheck] %systemroot%\system32\dumprep 0 -k
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_07\bin\jusched.exe"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files\MSN Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [Steam] "c:\program files\steam\steam.exe" -silent
O4 - HKCU\..\Run: [SpybotSD TeaTimer] C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
O4 - HKCU\..\Run: [ccleaner] "C:\Documents and Settings\Alpha\Bureau\ccleaner-crap-cleaner_ccleaner_portable_v2.12.6560_francais_14492\CCleaner.exe" /AUTO
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
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: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\Office12\REFIEBAR.DLL
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
O16 - DPF: {1E54D648-B804-468d-BC78-4AFFED8E262E} (System Requirements Lab) - https://www.nvidia.com/content/DriverDownload/srl/3.0.0.0/srl_bin/sysreqlab3.cab
O16 - DPF: {74DBCB52-F298-4110-951D-AD2FF67BC8AB} (NVIDIA Smart Scan) - https://www.nvidia.com/content/DriverDownload/nforce/NvidiaSmartScan.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
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: ##Id_String1.6844F930_1628_4223_B5CC_5BB94B879762## (Bonjour Service) - Apple Computer, Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: FLEXnet Licensing Service - Macrovision Europe Ltd. - C:\Program Files\Fichiers communs\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: wampapache - Apache Software Foundation - c:\wamp\bin\apache\apache2.2.8\bin\httpd.exe
O23 - Service: wampmysqld - Unknown owner - c:\wamp\bin\mysql\mysql5.0.51b\bin\mysqld-nt.exe