Virus et spams, pc infecté

Bonjour,

Mon adresse mail envoie apparemment des spams. Je le sais car j'en ai moi même recu dans la corbeille de tri de spamhilator.
En plus, avast me détecte un virus: svchost.exe. Mais est-ce vraiment un virus?

J'ai fait deux analyses: malwarebytes me dit ceci:

Malwarebytes' Anti-Malware 1.11
Version de la base de données: 606

Type de recherche: Examen complet (C:\|)
Eléments examinés: 152039
Temps écoulé: 59 minute(s), 36 second(s)

Processus mémoire infecté(s): 1
Module(s) mémoire infecté(s): 0
Clé(s) du Registre infectée(s): 0
Valeur(s) du Registre infectée(s): 1
Elément(s) de données du Registre infecté(s): 1
Dossier(s) infecté(s): 0
Fichier(s) infecté(s): 1

Processus mémoire infecté(s):
C:\WINDOWS\system\svchost.exe (Heuristics.Reserved.Word.Exploit) -> No action taken.

Module(s) mémoire infecté(s):
(Aucun élément nuisible détecté)

Clé(s) du Registre infectée(s):
(Aucun élément nuisible détecté)

Valeur(s) du Registre infectée(s):
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\URLSearchHooks\{4d25f926-b9fe-4682-bf72-8ab8210d6d75} (Adware.MyWay) -> No action taken.

Elément(s) de données du Registre infecté(s):
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit (Heuristics.Reserved.Word.Exploit) -> Data: c:\windows\system\svchost.exe -> No action taken.

Dossier(s) infecté(s):
(Aucun élément nuisible détecté)

Fichier(s) infecté(s):
C:\WINDOWS\system\svchost.exe (Heuristics.Reserved.Word.Exploit) -> No action taken.

et hijackthis:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 12:28:58, on 18/12/2008
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16762)
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:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Avira\AntiVir PersonalEdition Classic\sched.exe
C:\WINDOWS\system\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Avira\AntiVir PersonalEdition Classic\avguard.exe
C:\Program Files\Bonjour\mDNSResponder.exe
C:\Program Files\Fichiers communs\GtFlashSwitch\GtFlashSwitch.exe
C:\Program Files\Fichiers communs\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\Program Files\Microsoft SQL Server\MSSQL$MICROSOFTSMLBIZ\Binn\sqlservr.exe
C:\Program Files\Apoint\Apoint.exe
C:\WINDOWS\system32\hkcmd.exe
C:\WINDOWS\system32\igfxpers.exe
C:\WINDOWS\system32\igfxsrvc.exe
C:\Program Files\Java\j2re1.4.2_03\bin\jusched.exe
C:\WINDOWS\stsystra.exe
C:\Program Files\CyberLink\PowerDVD\DVDLauncher.exe
C:\Program Files\Dell\QuickSet\quickset.exe
C:\Program Files\Spamihilator\spamihilator.exe
C:\Program Files\Avira\AntiVir PersonalEdition Classic\avgnt.exe
C:\Program Files\NetWaiting\netWaiting.exe
C:\Program Files\MSN Messenger\MsnMsgr.Exe
C:\Program Files\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Toshiba\Bluetooth Toshiba Stack\TosBtMng.exe
C:\Program Files\Apoint\HidFind.exe
C:\Program Files\Digital Line Detect\DLG.exe
C:\Program Files\Apoint\Apntex.exe
C:\Program Files\Toshiba\Bluetooth Toshiba Stack\TosA2dp.exe
C:\Program Files\Mobistar\Mobistar Internet Everywhere\Mobistar Internet Everywhere.exe
C:\Program Files\Microsoft SQL Server\80\Tools\Binn\sqlmangr.exe
C:\Program Files\Toshiba\Bluetooth Toshiba Stack\TosBtHid.exe
C:\Program Files\Toshiba\Bluetooth Toshiba Stack\TosBtBty.exe
C:\Program Files\Toshiba\Bluetooth Toshiba Stack\TosBtHsp.exe
C:\Program Files\Toshiba\Bluetooth Toshiba Stack\tosOBEX.exe
C:\Program Files\Dell\NICCONFIGSVC\NICCONFIGSVC.exe
C:\WINDOWS\system32\PSIService.exe
C:\Program Files\Toshiba\Bluetooth Toshiba Stack\tosBtProc.exe
C:\Program Files\MSN Messenger\usnsvc.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Windows Media Player\wmplayer.exe
C:\Program Files\Outlook Express\msimn.exe
C:\Program Files\Malwarebytes' Anti-Malware\mbam.exe
C:\Program Files\Trend Micro\HijackThis\Hjt.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = https://www.dell.com/fr-fr
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.google.be/?gws_rd=ssl
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
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
R3 - URLSearchHook: (no name) - {4d25f926-b9fe-4682-bf72-8ab8210d6d75} - (no file)
F2 - REG:system.ini: UserInit=userinit.exe,C:\WINDOWS\system\svchost.exe
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - c:\program files\google\googletoolbar1.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Program Files\Google\GoogleToolbarNotifier\3.1.807.1746\swg.dll
O3 - Toolbar: &Google - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - c:\program files\google\googletoolbar1.dll
O4 - HKLM\..\Run: [Apoint] C:\Program Files\Apoint\Apoint.exe
O4 - HKLM\..\Run: [igfxtray] C:\WINDOWS\system32\igfxtray.exe
O4 - HKLM\..\Run: [igfxhkcmd] C:\WINDOWS\system32\hkcmd.exe
O4 - HKLM\..\Run: [igfxpers] C:\WINDOWS\system32\igfxpers.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\j2re1.4.2_03\bin\jusched.exe
O4 - HKLM\..\Run: [SigmatelSysTrayApp] stsystra.exe
O4 - HKLM\..\Run: [DVDLauncher] "C:\Program Files\CyberLink\PowerDVD\DVDLauncher.exe"
O4 - HKLM\..\Run: [Dell QuickSet] C:\Program Files\Dell\QuickSet\quickset.exe
O4 - HKLM\..\Run: [ShowLOMControl]
O4 - HKLM\..\Run: [JobHisInit] C:\Program Files\RMClient\JobHisInit.exe
O4 - HKLM\..\Run: [MplSetUp] C:\Program Files\RMClient\MplSetUp.exe
O4 - HKLM\..\Run: [Spamihilator] "C:\Program Files\Spamihilator\spamihilator.exe"
O4 - HKLM\..\Run: [avgnt] "C:\Program Files\Avira\AntiVir PersonalEdition Classic\avgnt.exe" /min
O4 - HKCU\..\Run: [ModemOnHold] C:\Program Files\NetWaiting\netWaiting.exe
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files\MSN Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [swg] C:\Program Files\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVICE RÉSEAU')
O4 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'Default user')
O4 - Global Startup: Bluetooth Manager.lnk = ?
O4 - Global Startup: Digital Line Detect.lnk = ?
O4 - Global Startup: Lancement rapide d'Adobe Reader.lnk = C:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Mobistar Internet Everywhere.lnk = C:\Program Files\Mobistar\Mobistar Internet Everywhere\Mobistar Internet Everywhere.exe
O4 - Global Startup: Service Manager.lnk = C:\Program Files\Microsoft SQL Server\80\Tools\Binn\sqlmangr.exe
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\j2re1.4.2_03\bin\npjpi142_03.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\j2re1.4.2_03\bin\npjpi142_03.dll
O9 - Extra button: (no name) - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe
O9 - Extra 'Tools' menuitem: Uninstall BitDefender Online Scanner v8 - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe
O9 - Extra button: Recherche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe (file missing)
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe (file missing)
O10 - Unknown file in Winsock LSP: c:\windows\system32\nwprovau.dll
O16 - DPF: {2917297F-F02B-4B9D-81DF-494B6333150B} (Minesweeper Flags Class) - http://messenger.zone.msn.com/binary/MineSweeper.cab31267.cab
O16 - DPF: {5D86DDB5-BDF9-441B-9E9E-D4730F4EE499} (BDSCANONLINE Control) - http://www.bitdefender.fr/scan_fr/scan8/oscan8.cab
O16 - DPF: {6E5E167B-1566-4316-B27F-0DDAB3484CF7} (Image Uploader Control) - http://www.new2.foto.com/ImageUploader4.cab
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsClient.cab31267.cab
O16 - DPF: {9A9307A0-7DA4-4DAF-B042-5009F29E09E1} (ActiveScan Installer Class) - http://acs.pandasoftware.com/activescan/as5free/asinst.cab
O16 - DPF: {C3F79A2B-B9B4-4A66-B012-3EE46475B072} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsPAClient.cab56907.cab
O16 - DPF: {DEB21AD3-FDA4-42F6-B57D-EE696A675EE8} (IPSUploader Control) - http://asp03.photoprintit.de/microsite/13571/defaults/activex/IPSUploader.cab
O16 - DPF: {F5A7706B-B9C0-4C89-A715-7A0C6B05DD48} (Minesweeper Flags Class) - http://messenger.zone.msn.com/binary/MineSweeper.cab56986.cab
O23 - Service: Avira AntiVir Personal – Free Antivirus Scheduler (AntiVirScheduler) - Avira GmbH - C:\Program Files\Avira\AntiVir PersonalEdition Classic\sched.exe
O23 - Service: Avira AntiVir Personal – Free Antivirus Guard (AntiVirService) - Avira GmbH - C:\Program Files\Avira\AntiVir PersonalEdition Classic\avguard.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: GtFlashSwitch - OptionNV - C:\Program Files\Fichiers communs\GtFlashSwitch\GtFlashSwitch.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: NICCONFIGSVC - Dell Inc. - C:\Program Files\Dell\NICCONFIGSVC\NICCONFIGSVC.exe
O23 - Service: ProtexisLicensing - Unknown owner - C:\WINDOWS\system32\PSIService.exe