Scusate mi potreste controllare il log dopo la scansione con Hijackthis qui sotto riportato:
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 16.36.15, on 19/09/2009
Platform: Windows Vista SP2 (WinNT 6.00.1906)
MSIE: Internet Explorer v8.00 (8.00.6001.18813)
Boot mode: Normal

Running processes:
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Windows\SYSTEM32\taskeng.exe
C:\Program Files\Windows Defender\MSASCui.exe
C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
C:\Acer\Empowering Technology\eDataSecurity\eDSLoader.exe
C:\Acer\Empowering Technology\eAudio\eAudio.exe
C:\Program Files\Launch Manager\QtZgAcer.EXE
C:\Program Files\Acer Arcade Deluxe\Play Movie\PMVService.exe
C:\Program Files\Intel\Intel Matrix Storage Manager\IAAnotif.exe
C:\Program Files\Alice ti aiuta\McciTrayApp.exe
C:\Windows\System32\rundll32.exe
C:\Program Files\Realtek\Audio\HDA\RtHDVCpl.exe
C:\Program Files\Adobe\Reader 9.0\Reader\reader_sl.exe
C:\Program Files\Windows Sidebar\sidebar.exe
C:\Windows\ehome\ehtray.exe
C:\Program Files\Windows Live\Messenger\msnmsgr.exe
C:\Windows\System32\rundll32.exe
C:\Program Files\Acer\Acer VCM\AcerVCM.exe
C:\Convesoft\Orion\Messenger.exe
C:\Windows\ehome\ehmsas.exe
C:\Acer\Empowering Technology\EPOWER\EPOWER_DMC.EXE
C:\Acer\Empowering Technology\ACER.EMPOWERING.FRAMEWORK.SUPERVISOR.EXE
C:\Acer\Empowering Technology\eRecovery\ERAGENT.EXE
C:\Users\SILVIA\AppData\Local\Temp\RtkBtMnt.exe
C:\Program Files\Acer\Acer VCM\VC.exe
C:\Program Files\Acer\Acer VCM\acp2HID.exe
C:\SCAN\HijackThis.exe
C:\Windows\system32\SearchFilterHost.exe
C:\Windows\system32\SearchProtocolHost.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://it.yahoo.com/
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://it.intl.acer.yahoo.com
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://it.rd.yahoo.com/customize/ycomp/defaults/su/*http://it.yahoo.com
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
O1 - Hosts: ::1 localhost
O2 - BHO: &Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: (no name) - {5C255C8A-E604-49b4-9D64-90988571CECB} - (no file)
O2 - BHO: Search Helper - {6EBF7485-159F-4bff-A14F-B9E3AAC4465B} - C:\Program Files\Microsoft\Search Enhancement Pack\Search Helper\SEPsearchhelperie.dll
O2 - BHO: Guida per l'accesso a Windows Live ID - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Easy Photo Print - {9421DD08-935F-4701-A9CA-22DF90AC4EA6} - C:\Program Files\Epson Software\Easy Photo Print\EPTBL.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - C:\Program Files\Google\Google Toolbar\GoogleToolbar_32.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Program Files\Google\GoogleToolbarNotifier\5.2.4204.1700\swg.dll
O2 - BHO: Google Dictionary Compression sdch - {C84D72FE-E17D-4195-BB24-76C02E2E7C4E} - C:\Program Files\Google\Google Toolbar\Component\fastsearch_B7C5AC242193BB3E.dll
O2 - BHO: Windows Live Toolbar Helper - {E15A8DC0-8516-42A1-81EA-DC94EC1ACF10} - C:\Program Files\Windows Live\Toolbar\wltcore.dll
O2 - BHO: SingleInstance Class - {FDAD4DA1-61A2-4FD8-9C17-86F7AC245081} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\YTSingleInstance.dll
O3 - Toolbar: Acer eDataSecurity Management - {5CBE3B7C-1E47-477e-A7DD-396DB0476E29} - C:\Windows\system32\eDStoolbar.dll
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O3 - Toolbar: Easy Photo Print - {9421DD08-935F-4701-A9CA-22DF90AC4EA6} - C:\Program Files\Epson Software\Easy Photo Print\EPTBL.dll
O3 - Toolbar: &Windows Live Toolbar - {21FA44EF-376D-4D53-9B0F-8A89D3229068} - C:\Program Files\Windows Live\Toolbar\wltcore.dll
O3 - Toolbar: Google Toolbar - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - C:\Program Files\Google\Google Toolbar\GoogleToolbar_32.dll
O4 - HKLM\..\Run: [Windows Defender] %ProgramFiles%\Windows Defender\MSASCui.exe -hide
O4 - HKLM\..\Run: [SynTPEnh] C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [eDataSecurity Loader] C:\Acer\Empowering Technology\eDataSecurity\eDSloader.exe
O4 - HKLM\..\Run: [eAudio] "C:\Acer\Empowering Technology\eAudio\eAudio.exe"
O4 - HKLM\..\Run: [PLFSet] rundll32.exe C:\Windows\PLFSet.dll,PLFDefSetting
O4 - HKLM\..\Run: [LManager] C:\PROGRA~1\LAUNCH~1\QtZgAcer.EXE
O4 - HKLM\..\Run: [PlayMovie] "C:\Program Files\Acer Arcade Deluxe\Play Movie\PMVService.exe"
O4 - HKLM\..\Run: [Acer Tour Reminder] C:\Acer\AcerTour\Reminder.exe
O4 - HKLM\..\Run: [WarReg_PopUp] C:\Acer\WR_PopUp\WarReg_PopUp.exe
O4 - HKLM\..\Run: [IAAnotif] C:\Program Files\Intel\Intel Matrix Storage Manager\iaanotif.exe
O4 - HKLM\..\Run: [AliceRV_McciTrayApp] C:\Program Files\Alice ti aiuta\McciTrayApp.exe
O4 - HKLM\..\Run: [NvSvc] RUNDLL32.EXE C:\Windows\system32\nvsvc.dll,nvsvcStart
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\Windows\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\Windows\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [Google Quick Search Box] "C:\Program Files\Google\Quick Search Box\GoogleQuickSearchBox.exe" /autorun
O4 - HKLM\..\Run: [RtHDVCpl] C:\Program Files\Realtek\Audio\HDA\RtHDVCpl.exe
O4 - HKLM\..\Run: [Skytel] C:\Program Files\Realtek\Audio\HDA\Skytel.exe
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 9.0\Reader\Reader_sl.exe"
O4 - HKCU\..\Run: [Sidebar] C:\Program Files\Windows Sidebar\sidebar.exe /autoRun
O4 - HKCU\..\Run: [WindowsWelcomeCenter] rundll32.exe oobefldr.dll,ShowWelcomeCenter
O4 - HKCU\..\Run: [ehTray.exe] C:\Windows\ehome\ehTray.exe
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\Windows Live\Messenger\msnmsgr.exe" /background
O4 - HKCU\..\Run: [swg] "C:\Program Files\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe"
O4 - Startup: Orion.lnk = C:\Convesoft\Orion\Messenger.exe
O4 - Global Startup: Acer VCM.lnk = ?
O4 - Global Startup: Empowering Technology Launcher.lnk = C:\Acer\Empowering Technology\eAPLauncher.exe
O9 - Extra button: Inserisci blog - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
O9 - Extra 'Tools' menuitem: Inserisci &blog in Windows Live Writer - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\Office12\REFIEBAR.DLL
O16 - DPF: {0742B9EF-8C83-41CA-BFBA-830A59E23533} (Microsoft Data Collection Control) - https://oas.support.microsoft.com/ActiveX/MSDcode.cab
O16 - DPF: {44990301-3C9D-426D-81DF-AAB636FA4345} (Symantec Script Runner Class) - https://www-secure.symantec.com/techsupp/asa/ss/sa/sa_cabs/tgctlsr.cab
O16 - DPF: {E2883E8F-472F-4FB0-9522-AC9BF37916A7} - http://platformdl.adobe.com/NOS/getPlusPlus/1.6/gp.cab
O23 - Service: ALaunch Service (ALaunchService) - Unknown owner - C:\Acer\ALaunch\ALaunchSvc.exe
O23 - Service: Symantec Lic NetConnect service (CLTNetCnService) - Unknown owner - C:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe (file missing)
O23 - Service: eDSService.exe (eDataSecurity Service) - HiTRSUT - C:\Acer\Empowering Technology\eDataSecurity\eDSService.exe
O23 - Service: eLock Service (eLockService) - Acer Inc. - C:\Acer\Empowering Technology\eLock\Service\eLockServ.exe
O23 - Service: eNet Service - Acer Inc. - C:\Acer\Empowering Technology\eNet\eNet Service.exe
O23 - Service: eRecovery Service (eRecoveryService) - Acer Inc. - C:\Acer\Empowering Technology\eRecovery\eRecoveryService.exe
O23 - Service: eSettings Service (eSettingsService) - Unknown owner - C:\Acer\Empowering Technology\eSettings\Service\capuserv.exe
O23 - Service: Intel® PROSet/Wireless Event Log (EvtEng) - Intel(R) Corporation - C:\Program Files\Intel\WiFi\bin\EvtEng.exe
O23 - Service: Servizio di Google Update (gupdate1c9934c36028412) (gupdate1c9934c36028412) - Google Inc. - C:\Program Files\Google\Update\GoogleUpdate.exe
O23 - Service: Google Software Updater (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: Intel(R) Matrix Storage Event Monitor (IAANTMON) - Intel Corporation - C:\Program Files\Intel\Intel Matrix Storage Manager\IAANTMon.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - C:\Program Files\Common Files\LightScribe\LSSrvc.exe
O23 - Service: MobilityService - Unknown owner - C:\Acer\Mobility Center\MobilityService.exe
O23 - Service: Intel® PROSet/Wireless Registry Service (RegSrvc) - Intel(R) Corporation - C:\Program Files\Common Files\Intel\WirelessCommon\RegSrvc.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Program Files\CyberLink\Shared Files\RichVideo.exe
O23 - Service: ePower Service (WMIService) - acer - C:\Acer\Empowering Technology\ePower\ePowerSvc.exe
O23 - Service: XAudioService - Conexant Systems, Inc. - C:\Windows\system32\DRIVERS\xaudio.exe

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End of file - 9825 bytes
Distinti saluti.

Anche qui hai sbagliato sezione, devi postare in Sicurezza e virus, poi devi dire che problema riscontri,
ho notato che hai un sacco di toolbar, questo causa rallentamenti e alle volte blocchi, se usi Google come motore di ricerca, tieni solo quella e alimina tutte le altre, non servono a niente, ma creano solo caos.

Il log è pulito ma nel sistema non hai installato ne un antivirus ne un firewall, strano che sia pulito.

Installa questo antivirus
http://www.aiutamici.com/software?ID=80367

instala questo Firewall
http://www.aiutamici.com/software?ID=80361


Una volta terminato l'installazione, fai l'aggiornamento dell'antivirus e lancia una scansione completa.

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alfonso_aiutamici@hotmail.it