Sì, devi farlo in modalità provvisoria. Leggi i primi tre punti. <b>Non</b> devi assolutamente essere connessa durante la procedura.

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Ho seguito la tua procedura ma continuo a non poter accedere alle mail, a non poter utilizzare username e password, tra l'altro, appena accedo al pc mi esce un rettangolo con un avviso "Hcontrol.exe impossibile individuare un componente dell'applicazione.
Impossibile avviare l'applicazione specifica CMSSC.dll una nuova installazione potrebbe risolvere il problema"

Ti posto il nuovo log:
Logfile of HijackThis v1.99.1
Scan saved at 10.47.57, on 01/06/2007
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\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Programmi\AntiVir PersonalEdition Classic\sched.exe
C:\Programmi\AntiVir PersonalEdition Classic\avguard.exe
C:\WINDOWS\ATKKBService.exe
C:\Programmi\File comuni\McAfee\HackerWatch\HWAPI.exe
c:\programmi\file comuni\mcafee\mna\mcnasvc.exe
C:\PROGRA~1\McAfee\VIRUSS~1\mcods.exe
c:\PROGRA~1\FILECO~1\mcafee\redirsvc\redirsvc.exe
C:\Programmi\File comuni\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\Programmi\McAfee\MPF\MPFSrv.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\WgaTray.exe
C:\WINDOWS\system32\wscntfy.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\ATK0100\Hcontrol.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\Programmi\AntiVir PersonalEdition Classic\avgnt.exe
C:\Programmi\Alice ti aiuta\bin\mpbtn.exe
C:\Programmi\Internet Explorer\iexplore.exe
C:\Programmi\Internet Explorer\IEXPLORE.EXE
C:\WINDOWS\system32\Restore\rstrui.exe
D:\Pisano\Desktop\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.libero.it/
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page =
R1 - HKCU\Software\Microsoft\Internet Connection Wizard,ShellNext = http://www.google.it/
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Programmi\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\Programmi\Spybot - Search & Destroy\SDHelper.dll
O3 - Toolbar: Easy-WebPrint - {327C2873-E90D-4c37-AA9D-10AC9BABA46C} - C:\Programmi\Canon\Easy-WebPrint\Toolband.dll
O4 - HKLM\..\Run: [Hcontrol] C:\WINDOWS\ATK0100\Hcontrol.exe
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [ATIPTA] C:\Programmi\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [HSFPWCFG.EXE] C:\WINDOWS\HSFPWCFG.EXE
O4 - HKLM\..\Run: [SynTPLpr] C:\Programmi\Synaptics\SynTP\SynTPLpr.exe
O4 - HKLM\..\Run: [SynTPEnh] C:\Programmi\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [NeroFilterCheck] C:\WINDOWS\system32\NeroCheck.exe
O4 - HKLM\..\Run: [Easy-PrintToolBox] C:\Programmi\Canon\Easy-PrintToolBox\BJPSMAIN.EXE /logon
O4 - HKLM\..\Run: [MessengerPlus3] "C:\Programmi\MessengerPlus! 3\MsgPlus.exe"
O4 - HKLM\..\Run: [avgnt] "C:\Programmi\AntiVir PersonalEdition Classic\avgnt.exe" /min
O4 - HKCU\..\Run: [updateMgr] "C:\Programmi\Adobe\Acrobat 7.0\Reader\AdobeUpdateManager.exe" AcRdB7_0_8 -reboot 1
O4 - Global Startup: Adobe Gamma Loader.lnk = C:\Programmi\File comuni\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Global Startup: Alice ti aiuta.lnk = C:\Programmi\Alice ti aiuta\bin\matcli.exe
O4 - Global Startup: Avvio veloce di Adobe Reader.lnk = C:\Programmi\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O8 - Extra context menu item: Aggiungi all'elenco di stampa Easy-WebPrint - res://C:\Programmi\Canon\Easy-WebPrint\Resource.dll/RC_AddToList.html
O8 - Extra context menu item: Anteprima Easy-WebPrint - res://C:\Programmi\Canon\Easy-WebPrint\Resource.dll/RC_Preview.html
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O8 - Extra context menu item: Stampa ad alta velocità Easy-WebPrint - res://C:\Programmi\Canon\Easy-WebPrint\Resource.dll/RC_HSPrint.html
O8 - Extra context menu item: Stampa Easy-WebPrint - res://C:\Programmi\Canon\Easy-WebPrint\Resource.dll/RC_Print.html
O15 - Trusted Zone: *.whataboutarabit.com
O16 - DPF: {193C772A-87BE-4B19-A7BB-445B226FE9A1} (ewidoOnlineScan Control) - http://download.ewido.net/ewidoOnlineScan.cab
O16 - DPF: {5D86DDB5-BDF9-441B-9E9E-D4730F4EE499} (BDSCANONLINE Control) - http://download.bitdefender.com/resources/scan8/oscan8.cab
O16 - DPF: {644E432F-49D3-41A1-8DD5-E099162EEEC5} (Symantec RuFSI Utility Class) - http://security.symantec.com/sscv6/SharedContent/common/bin/cabsa.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{4CECA580-AA1F-4E8E-B025-C05CC282B1C5}: NameServer = 85.37.17.58 85.38.28.94
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - "C:\PROGRA~1\MSNMES~1\msgrapp.dll" (file missing)
O18 - Protocol: siteadvisor - {3A5DC592-7723-4EAA-9EE6-AF4222BCF879} - (no file)
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll
O23 - Service: AntiVir PersonalEdition Classic Scheduler (AntiVirScheduler) - Avira GmbH - C:\Programmi\AntiVir PersonalEdition Classic\sched.exe
O23 - Service: AntiVir PersonalEdition Classic Guard (AntiVirService) - AVIRA GmbH - C:\Programmi\AntiVir PersonalEdition Classic\avguard.exe
O23 - Service: Ati HotKey Poller - Unknown owner - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: ATK Keyboard Service (ATKKeyboardService) - ASUSTeK COMPUTER INC. - C:\WINDOWS\ATKKBService.exe
O23 - Service: McAfee E-mail Proxy (Emproxy) - McAfee, Inc. - C:\PROGRA~1\FILECO~1\McAfee\EmProxy\emproxy.exe
O23 - Service: McAfee HackerWatch Service - McAfee, Inc. - C:\Programmi\File comuni\McAfee\HackerWatch\HWAPI.exe
O23 - Service: McAfee Update Manager (mcmispupdmgr) - McAfee, Inc. - C:\PROGRA~1\McAfee\MSC\mcupdmgr.exe
O23 - Service: McAfee Services (mcmscsvc) - McAfee, Inc. - (no file)
O23 - Service: McAfee Network Agent (McNASvc) - McAfee, Inc. - c:\programmi\file comuni\mcafee\mna\mcnasvc.exe
O23 - Service: McAfee Scanner (McODS) - McAfee, Inc. - C:\PROGRA~1\McAfee\VIRUSS~1\mcods.exe
O23 - Service: McAfee Protection Manager (mcpromgr) - McAfee, Inc. - (no file)
O23 - Service: McAfee Redirector Service (McRedirector) - McAfee, Inc. - c:\PROGRA~1\FILECO~1\mcafee\redirsvc\redirsvc.exe
O23 - Service: McAfee Real-time Scanner (McShield) - McAfee, Inc. - C:\PROGRA~1\McAfee\VIRUSS~1\mcshield.exe
O23 - Service: McAfee SystemGuards (McSysmon) - McAfee, Inc. - C:\PROGRA~1\McAfee\VIRUSS~1\mcsysmon.exe
O23 - Service: McAfee Personal Firewall Service (MpfService) - McAfee, Inc. - C:\Programmi\McAfee\MPF\MPFSrv.exe
O23 - Service: SiteAdvisor Service - SiS Corporation - (no file)

Poi mi chiedo perchè io ho ancora file con McAfee quando non mi risulta più come antivirus, avendolo disinstallato, perchè ho ancora il firewall attivo di McAfee?
Aiuto :(

dai riprova seguendo alla lettere quanto consigliato, non lasciarci in ansia!!!!