Sécuriser mon ordi + Virus

Bonjour,

J'aurais besoin d'aide pour sécuriser mon ordinateur de bureau ainsi que pour voir si des virus s'y sont logés.

Pour l'heure je ne dispose d'aucun anti-virus. J'ai la possibilité d'installer Norton fournis avec les CD de ma nouvelle carte-mère, mais j'attends vos avis si un anti-virus gratuit et mieux que ce dernier (genre Avira), que me conseillez-vous ?

Je vous post également mon rapport HiJackThis ain de voir si mon ordinateur est infecté :

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 18:43:28, on 25.04.2013
Platform: Unknown Windows (WinNT 6.01.3505 SP1)
MSIE: Internet Explorer v9.00 (9.00.8112.16476)
Boot mode: Normal

Running processes:
C:\Program Files (x86)\Intel\Intel(R) USB 3.0 eXtensible Host Controller Driver\Application\iusb3mon.exe
C:\Program Files (x86)\Intel\Intel(R) Rapid Storage Technology\IAStorIcon.exe
C:\Users\walzou\AppData\Local\Smartbar\Application\QuickShare.exe
C:\Program Files (x86)\Mozilla Firefox\firefox.exe
C:\Program Files (x86)\Mozilla Firefox\plugin-container.exe
C:\Windows\SysWOW64\Macromed\Flash\FlashPlayerPlugin_11_7_700_169.exe
C:\Windows\SysWOW64\Macromed\Flash\FlashPlayerPlugin_11_7_700_169.exe
C:\Program Files (x86)\Trend Micro\HijackThis\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.google.ch/?gws_rd=ssl
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page = C:\Windows\SysWOW64\blank.htm
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
F2 - REG:system.ini: UserInit=userinit.exe
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files (x86)\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: QuickShare WidgetEngine - {31ad400d-1b06-4e33-a59a-90c2c140cba0} - mscoree.dll (file missing)
O3 - Toolbar: QuickShare Widget - {ae07101b-46d4-4a98-af68-0333ea26e113} - mscoree.dll (file missing)
O4 - HKLM\..\Run: [USB3MON] "C:\Program Files (x86)\Intel\Intel(R) USB 3.0 eXtensible Host Controller Driver\Application\iusb3mon.exe"
O4 - HKLM\..\Run: [IAStorIcon] C:\Program Files (x86)\Intel\Intel(R) Rapid Storage Technology\IAStorIconLaunch.exe "C:\Program Files (x86)\Intel\Intel(R) Rapid Storage Technology\IAStorIcon.exe" 60
O4 - HKLM\..\Run: [StartCCC] "C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static\CLIStart.exe" MSRun
O4 - HKLM\..\Run: [Adobe ARM] "C:\Program Files (x86)\Common Files\Adobe\ARM\1.0\AdobeARM.exe"
O4 - HKCU\..\Run: [Browser Infrastructure Helper] C:\Users\walzou\AppData\Local\Smartbar\Application\QuickShare.exe startup
O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-19\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVICE RÉSEAU')
O4 - HKUS\S-1-5-20\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'SERVICE RÉSEAU')
O11 - Options group: [ACCELERATED_GRAPHICS] Accelerated graphics
O13 - Gopher Prefix:
O23 - Service: Adobe Acrobat Update Service (AdobeARMservice) - Adobe Systems Incorporated - C:\Program Files (x86)\Common Files\Adobe\ARM\1.0\armsvc.exe
O23 - Service: Adobe Flash Player Update Service (AdobeFlashPlayerUpdateSvc) - Adobe Systems Incorporated - C:\Windows\SysWOW64\Macromed\Flash\FlashPlayerUpdateService.exe
O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing)
O23 - Service: AMD External Events Utility - Unknown owner - C:\Windows\system32\atiesrxx.exe (file missing)
O23 - Service: DTSAudioSvc - DTS, Inc - C:\Program Files\Realtek\Audio\HDA\DTSU2PAuSrv64.exe
O23 - Service: @%SystemRoot%\system32\efssvc.dll,-100 (EFS) - Unknown owner - C:\Windows\System32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\fxsresm.dll,-118 (Fax) - Unknown owner - C:\Windows\system32\fxssvc.exe (file missing)
O23 - Service: Intel(R) Rapid Storage Technology (IAStorDataMgrSvc) - Intel Corporation - C:\Program Files (x86)\Intel\Intel(R) Rapid Storage Technology\IAStorDataMgrSvc.exe
O23 - Service: Intel(R) Capability Licensing Service Interface - Intel(R) Corporation - C:\Program Files\Intel\iCLS Client\HeciServer.exe
O23 - Service: Intel(R) PROSet Monitoring Service - Unknown owner - C:\Windows\system32\IProsetMonitor.exe (file missing)
O23 - Service: Intel(R) Dynamic Application Loader Host Interface Service (jhi_service) - Intel Corporation - C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL\jhi_service.exe
O23 - Service: @keyiso.dll,-100 (KeyIso) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: Intel(R) Management and Security Application Local Management Service (LMS) - Intel Corporation - C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\LMS\LMS.exe
O23 - Service: Mozilla Maintenance Service (MozillaMaintenance) - Mozilla Foundation - C:\Program Files (x86)\Mozilla Maintenance Service\maintenanceservice.exe
O23 - Service: @comres.dll,-2797 (MSDTC) - Unknown owner - C:\Windows\System32\msdtc.exe (file missing)
O23 - Service: @%SystemRoot%\System32\netlogon.dll,-102 (Netlogon) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
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\snmptrap.exe,-3 (SNMPTRAP) - Unknown owner - C:\Windows\System32\snmptrap.exe (file missing)
O23 - Service: @%systemroot%\system32\spoolsv.exe,-1 (Spooler) - Unknown owner - C:\Windows\System32\spoolsv.exe (file missing)
O23 - Service: @%SystemRoot%\system32\sppsvc.exe,-101 (sppsvc) - Unknown owner - C:\Windows\system32\sppsvc.exe (file missing)
O23 - Service: @%SystemRoot%\system32\ui0detect.exe,-101 (UI0Detect) - Unknown owner - C:\Windows\system32\UI0Detect.exe (file missing)
O23 - Service: Intel(R) Management and Security Application User Notification Service (UNS) - Intel Corporation - C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\UNS\UNS.exe
O23 - Service: @%SystemRoot%\system32\vaultsvc.dll,-1003 (VaultSvc) - Unknown owner - C:\Windows\system32\lsass.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\Wat\WatUX.exe,-601 (WatAdminSvc) - Unknown owner - C:\Windows\system32\Wat\WatAdminSvc.exe (file missing)
O23 - Service: @%systemroot%\system32\wbengine.exe,-104 (wbengine) - Unknown owner - C:\Windows\system32\wbengine.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)