Disparition des fichiers .exe

Salut à tous,
P'tit problème: les fichiers .exe des divers anti-virus disparaissent dès la fin de l'installation, idem pour certains logiciels d'analyse; l'analyse en ligne ne marche pas non plus.
Autre symptômes: le PC rame, surtout au démarrage et dans IE, une dizaine de sites se connectent automatiquement (comme j'utilise fire fox je ne l'ai pas vu de suite).
Donc, spécialiste de la lecture des rapports HijackThis, je vous laisse plancher sur celui ci:
Logfile of HijackThis v1.99.1
Scan saved at 14:11:40, on 20/07/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)

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:\Program Files\Windows Defender\MsMpEng.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\HPZipm12.exe
C:\WINDOWS\System32\tcpsvcs.exe
C:\WINDOWS\System32\snmp.exe
C:\Program Files\Alcohol Soft\Alcohol 120\StarWind\StarWindService.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Windows Defender\MSASCui.exe
C:\Program Files\Java\jre1.5.0_07\bin\jusched.exe
C:\Program Files\HP\HP Software Update\HPWuSchd2.exe
C:\WINDOWS\system32\ctfmon.exe
C:\WINDOWS\system32\svchost.exe
C:\Program Files\Messenger\msmsgs.exe
E:\Program Files\emule\0.48a Xt 6.0\emule0.48a-Xtreme6.0\emule.exe
C:\WINDOWS\System32\svchost.exe
C:\DOCUME~1\CHRIST~1\LOCALS~1\Temp\88exinjs.aa.exe
C:\PROGRA~1\MOZILL~1\FIREFOX.EXE
C:\WINDOWS\system32\svchost.exe
c:\program files\a-squared free\a2service.exe
C:\Hijackthis\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = https://www.bing.com/?toHttps=1&redig=5FC791212101479BAFBE1A679848B1AF
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,First Home Page = https://support.microsoft.com/en-US/topic/internet-explorer-downloads-d49e1f0d-571c-9a7b-d97e-be248806ca70
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyServer = proxy.mls.nc:8000
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\Program Files\Spybot - Search & Destroy\SDHelper.dll
O2 - BHO: (no name) - {549B5CA7-4A86-11D7-A4DF-000874180BB3} - (no file)
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0_02\bin\ssv.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Fichiers communs\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: (no name) - {FDD3B846-8D59-4ffb-8758-209B6AD74ACC} - (no file)
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: [KernelFaultCheck] %systemroot%\system32\dumprep 0 -k
O4 - HKLM\..\Run: [Windows Defender] "C:\Program Files\Windows Defender\MSASCui.exe" -hide
O4 - HKLM\..\Run: [TkBellExe] "C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_02\bin\jusched.exe"
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [PRONoMgr.exe] C:\Program Files\Intel\NCS\PROSet\PRONoMgr.exe
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [HP Software Update] c:\Program Files\HP\HP Software Update\HPWuSchd2.exe
O4 - HKLM\..\Run: [ATIPTA] C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [.nvsvc] C:\WINDOWS\system\smss.exe /w
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [SpybotSD TeaTimer] C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_02\bin\npjpi160_02.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_02\bin\npjpi160_02.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
O16 - DPF: {17492023-C23A-453E-A040-C7C580BBF700} (Windows Genuine Advantage Validation Tool) - http://download.microsoft.com/download/E/5/6/E5611B10-0D6D-4117-8430-A67417AA88CD/LegitCheckControl.cab
O16 - DPF: {30528230-99f7-4bb4-88d8-fa1d4f56a2ab} (YInstStarter Class) - C:\Program Files\Yahoo!\Common\yinsthelper.dll
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://update.microsoft.com/...
O17 - HKLM\System\CCS\Services\Tcpip\..\{798E10EC-4A24-461A-B65A-0EF0F32F976B}: NameServer = ###.##.###.# ###.##.###.#
O17 - HKLM\System\CS1\Services\Tcpip\..\{798E10EC-4A24-461A-B65A-0EF0F32F976B}: NameServer = ###.##.###.# ###.##.###.#
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\WI1F86~1\MESSEN~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\WI1F86~1\MESSEN~1\MSGRAP~1.DLL
O23 - Service: a-squared Free Service (a2free) - Emsi Software GmbH - c:\program files\a-squared free\a2service.exe
O23 - Service: ATI Smart - Unknown owner - C:\WINDOWS\system32\ati2sgag.exe
O23 - Service: Autodesk Licensing Service - Autodesk - C:\Program Files\Fichiers communs\Autodesk Shared\Service\AdskScSrv.exe
O23 - Service: DVD-RAM_Service - Matsushita Electric Industrial Co., Ltd. - C:\WINDOWS\system32\DVDRAMSV.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Fichiers communs\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: Intel NCS NetService (NetSvc) - Intel(R) Corporation - C:\Program Files\Intel\NCS\Sync\NetSvc.exe
O23 - Service: Pml Driver HPZ12 - HP - C:\WINDOWS\system32\HPZipm12.exe
O23 - Service: StarWind iSCSI Service (StarWindService) - Rocket Division Software - C:\Program Files\Alcohol Soft\Alcohol 120\StarWind\StarWindService.exe
O23 - Service: Windows Live Setup Service (WLSetupSvc) - Unknown owner - C:\Program Files\Windows Live\installer\WLSetupSvc.exe

Dans l'attente d'une réponse rapide, je vous souhaite bon courage et vous remercie par avance.
Labuche