Fichier Isass.exe manquant + bugs

Bonjour,
voici mon problème :
tout est partis d'un petit bug qui m'affichais les lettres de l'alphabet en haut à gauche de mon bureau mais qui ce bug a disparut une fois ma session relancée.
suite à ce problème qui m'inquiètais j'ai fais plusieurs analyses antivirus avec Avast, Malwarebyte's et S&D, mais rien, j'ai aussi fais un rapport HiJackthis, et là on a découvert qu'il me manquait le fichier Isass.exe...

un peu plus tôt, mon pc c'est éteins tout seul..

je ne sais plus quoi faire
quelqu'un peu m'aider ?

je poste un rapport Hijackthis si ça peut aider quelqu'un...

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 13:50:54, on 24/08/2009
Platform: Windows Vista SP1 (WinNT 6.00.1905)
MSIE: Internet Explorer v7.00 (7.00.6001.18294)
Boot mode: Normal

Running processes:
C:\Program Files (x86)\Windows Live\Messenger\msnmsgr.exe
C:\Program Files (x86)\Windows Media Player\wmplayer.exe
C:\Program Files (x86)\Steam\Steam.exe
C:\Program Files (x86)\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe
C:\Program Files (x86)\Spybot - Search & Destroy\TeaTimer.exe
C:\Program Files (x86)\Common Files\Nero\Lib\NMIndexStoreSvr.exe
C:\Program Files (x86)\Electronic Arts\EADM\Core.exe
C:\Program Files (x86)\Samsung\Samsung New PC Studio\NPSAgent.exe
C:\Program Files (x86)\Netlog Music Tool\NetlogMusicTool.exe
C:\Program Files\Alwil Software\Avast4\ashDisp.exe
C:\Program Files (x86)\Common Files\LogiShrd\LComMgr\Communications_Helper.exe
C:\Program Files (x86)\Micro Application\LauncherMA.exe
C:\Program Files (x86)\Sony\Sony Picture Utility\PMBCore\SPUVolumeWatcher.exe
C:\Program Files (x86)\Logitech\QuickCam\Quickcam.exe
C:\Program Files (x86)\Unlocker\UnlockerAssistant.exe
C:\Program Files (x86)\Java\jre6\bin\jusched.exe
C:\Program Files (x86)\iTunes\iTunesHelper.exe
C:\Program Files (x86)\OpenOffice.org 3\program\soffice.exe
C:\Program Files (x86)\Last.fm\LastFM.exe
C:\Program Files (x86)\Common Files\Logishrd\LQCVFX\COCIManager.exe
C:\Program Files (x86)\OpenOffice.org 3\program\soffice.bin
C:\Windows\SysWOW64\conime.exe
C:\Program Files (x86)\Windows Live\Contacts\wlcomm.exe
C:\Program Files (x86)\Mozilla Firefox\firefox.exe
C:\Users\WildChild\Desktop\HiJackThis.exe
C:\Windows\SysWOW64\DllHost.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://moteur.chat-land.org/
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 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
F2 - REG:system.ini: UserInit=C:\Windows\SysWOW64\userinit.exe,
O1 - Hosts: ::1 localhost
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files (x86)\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: Spybot-S&D IE Protection - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~2\SPYBOT~1\SDHelper.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 (x86)\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Program Files (x86)\Google\GoogleToolbarNotifier\5.1.1309.15642\swg.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files (x86)\Java\jre6\bin\jp2ssv.dll
O4 - HKLM\..\Run: [Google Desktop Search] "C:\Program Files (x86)\Google\Google Desktop Search\GoogleDesktop.exe" /startup
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [LogitechCommunicationsManager] "C:\Program Files (x86)\Common Files\LogiShrd\LComMgr\Communications_Helper.exe"
O4 - HKLM\..\Run: [LogitechQuickCamRibbon] "C:\Program Files (x86)\Logitech\QuickCam\Quickcam.exe" /hide
O4 - HKLM\..\Run: [AppleSyncNotifier] C:\Program Files (x86)\Common Files\Apple\Mobile Device Support\bin\AppleSyncNotifier.exe
O4 - HKLM\..\Run: [UnlockerAssistant] "C:\Program Files (x86)\Unlocker\UnlockerAssistant.exe"
O4 - HKLM\..\Run: [NBKeyScan] "C:\Program Files (x86)\Nero\Nero8\Nero BackItUp\NBKeyScan.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files (x86)\Java\jre6\bin\jusched.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files (x86)\Adobe\Reader 9.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files (x86)\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files (x86)\iTunes\iTunesHelper.exe"
O4 - HKCU\..\Run: [Sidebar] C:\Program Files\Windows Sidebar\sidebar.exe /autoRun
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files (x86)\Windows Live\Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [Steam] "C:\Program Files (x86)\Steam\Steam.exe" -silent
O4 - HKCU\..\Run: [ehTray.exe] C:\Windows\ehome\ehTray.exe
O4 - HKCU\..\Run: [swg] C:\Program Files (x86)\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe
O4 - HKCU\..\Run: [SpybotSD TeaTimer] C:\Program Files (x86)\Spybot - Search & Destroy\TeaTimer.exe
O4 - HKCU\..\Run: [Comrade.exe] C:\Program Files (x86)\GameSpy\Comrade\Comrade.exe
O4 - HKCU\..\Run: [IndxStoreSvr_{79662E04-7C6C-4d9f-84C7-88D8A56B10AA}] "C:\Program Files (x86)\Common Files\Nero\Lib\NMIndexStoreSvr.exe" ASO-616B5711-6DAE-4795-A05F-39A1E5104020
O4 - HKCU\..\Run: [EA Core] C:\Program Files (x86)\Electronic Arts\EADM\Core.exe -silent
O4 - HKCU\..\Run: [EPSON SX100 Series] C:\Windows\system32\spool\DRIVERS\x64\3\E_IATIEDE.EXE /FU "C:\Windows\TEMP\E_S701C.tmp" /EF "HKCU"
O4 - HKCU\..\Run: [AutoStartNPSAgent] C:\Program Files (x86)\Samsung\Samsung New PC Studio\NPSAgent.exe
O4 - HKCU\..\Run: [Netlog Music Tool] "C:\Program Files (x86)\Netlog Music Tool\NetlogMusicTool.exe"
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 - Startup: Lanceur.lnk = C:\Program Files (x86)\Micro Application\LauncherMA.exe
O4 - Startup: OpenOffice.org 3.0.lnk = C:\Program Files (x86)\OpenOffice.org 3\program\quickstart.exe
O4 - Startup: Outil de détection de support PMB.lnk = C:\Program Files (x86)\Sony\Sony Picture Utility\PMBCore\SPUVolumeWatcher.exe
O9 - Extra button: (no name) - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~2\SPYBOT~1\SDHelper.dll
O9 - Extra 'Tools' menuitem: Spybot - Search & Destroy Configuration - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~2\SPYBOT~1\SDHelper.dll
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files (x86)\Messenger\MSMSGS.EXE
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files (x86)\Messenger\MSMSGS.EXE
O13 - Gopher Prefix:
O16 - DPF: {C3F79A2B-B9B4-4A66-B012-3EE46475B072} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsPAClient.cab56907.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O20 - AppInit_DLLs: C:\PROGRA~2\Google\GOOGLE~2\GOEC62~1.DLL
O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing)
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files (x86)\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
O23 - Service: Service d'état ASP.NET (aspnet_state) - Unknown owner - C:\Windows\Microsoft.NET\Framework\v2.0.50727\aspnet_state.exe (file missing)
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 (x86)\Bonjour\mDNSResponder.exe
O23 - Service: @dfsrres.dll,-101 (DFSR) - Unknown owner - C:\Windows\system32\DFSR.exe (file missing)
O23 - Service: FLEXnet Licensing Service - Macrovision Europe Ltd. - C:\Program Files (x86)\Common Files\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: GoogleDesktopManager - Google - C:\Program Files (x86)\Google\Google Desktop Search\GoogleDesktopManager.exe
O23 - Service: Google Software Updater (gusvc) - Google - C:\Program Files (x86)\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files (x86)\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: Service de l’iPod (iPod Service) - Apple Inc. - C:\Program Files (x86)\iPod\bin\iPodService.exe
O23 - Service: @keyiso.dll,-100 (KeyIso) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: LVCOMSer - Logitech Inc. - C:\Program Files\Common Files\LogiShrd\LVCOMSER\LVCSer64.exe
O23 - Service: Process Monitor (LVPrcS64) - Logitech Inc. - C:\Program Files\Common Files\LogiShrd\LVMVFM\LVPrcSrv.exe
O23 - Service: MSCSPTISRV - Sony Corporation - C:\Program Files (x86)\Common Files\Sony Shared\AVLib\MSCSPTISRV.exe
O23 - Service: @comres.dll,-2797 (MSDTC) - Unknown owner - C:\Windows\System32\msdtc.exe (file missing)
O23 - Service: Nero BackItUp Scheduler 3 - Nero AG - C:\Program Files (x86)\Nero\Nero8\Nero BackItUp\NBService.exe
O23 - Service: @%SystemRoot%\System32\netlogon.dll,-102 (Netlogon) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: NMIndexingService - Nero AG - C:\Program Files (x86)\Common Files\Nero\Lib\NMIndexingService.exe
O23 - Service: NVIDIA Display Driver Service (nvsvc) - Unknown owner - C:\Windows\system32\nvvsvc.exe (file missing)
O23 - Service: PACSPTISVR - Unknown owner - C:\Program Files (x86)\Common Files\Sony Shared\AVLib\PACSPTISVR.exe
O23 - Service: PLFlash DeviceIoControl Service - Prolific Technology Inc. - C:\Windows\SysWOW64\IoctlSvc.exe
O23 - Service: PnkBstrA - Unknown owner - C:\Windows\system32\PnkBstrA.exe
O23 - Service: @%systemroot%\system32\psbase.dll,-300 (ProtectedStorage) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\Locator.exe,-2 (RpcLocator) - Unknown owner - C:\Windows\system32\locator.exe (file missing)
O23 - Service: @%SystemRoot%\system32\samsrv.dll,-1 (SamSs) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%SystemRoot%\system32\SLsvc.exe,-101 (slsvc) - Unknown owner - C:\Windows\system32\SLsvc.exe (file missing)
O23 - Service: @%SystemRoot%\system32\snmptrap.exe,-3 (SNMPTRAP) - Unknown owner - C:\Windows\System32\snmptrap.exe (file missing)
O23 - Service: SonicStage Back-End Service - Sony Corporation - C:\Program Files (x86)\Common Files\Sony Shared\AVLib\SsBeSvc.exe
O23 - Service: @%systemroot%\system32\spoolsv.exe,-1 (Spooler) - Unknown owner - C:\Windows\System32\spoolsv.exe (file missing)
O23 - Service: Sony SPTI Service (SPTISRV) - Sony Corporation - C:\Program Files (x86)\Common Files\Sony Shared\AVLib\SPTISRV.exe
O23 - Service: SonicStage SCSI Service (SSScsiSV) - Sony Corporation - C:\Program Files (x86)\Common Files\Sony Shared\AVLib\SSScsiSV.exe
O23 - Service: Steam Client Service - Valve Corporation - C:\Program Files (x86)\Common Files\Steam\SteamService.exe
O23 - Service: @%SystemRoot%\system32\ui0detect.exe,-101 (UI0Detect) - Unknown owner - C:\Windows\system32\UI0Detect.exe (file missing)
O23 - Service: @%SystemRoot%\system32\vds.exe,-100 (vds) - Unknown owner - C:\Windows\System32\vds.exe (file missing)
O23 - Service: @%systemroot%\system32\vssvc.exe,-102 (VSS) - Unknown owner - C:\Windows\system32\vssvc.exe (file missing)
O23 - Service: @%Systemroot%\system32\wbem\wmiapsrv.exe,-110 (wmiApSrv) - Unknown owner - C:\Windows\system32\wbem\WmiApSrv.exe (file missing)
O23 - Service: @%ProgramFiles%\Windows Media Player\wmpnetwk.exe,-101 (WMPNetworkSvc) - Unknown owner - C:\Program Files (x86)\Windows Media Player\wmpnetwk.exe (file missing)