ciao premetto uso firefox con il blocco flaggato ma all'apertura della volpe mi si aprono delle finestre vi allego il Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 11:38:31, on 08/03/2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16791)
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:\Programmi\COMODO\Firewall\cmdagent.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Programmi\Avira\AntiVir PersonalEdition Classic\sched.exe
C:\WINDOWS\Explorer.EXE
C:\Programmi\a-squared Free\a2service.exe
C:\Programmi\Avira\AntiVir PersonalEdition Classic\avguard.exe
C:\Programmi\Malwarebytes' Anti-Malware\mbamservice.exe
C:\WINDOWS\system32\oodag.exe
C:\Programmi\COMODO\Firewall\cfp.exe
C:\WINDOWS\system32\svchost.exe
C:\Programmi\Avira\AntiVir PersonalEdition Classic\avgnt.exe
C:\WINDOWS\system32\rundll32.exe
C:\Programmi\eMule\emule.exe
C:\Programmi\Mozilla Firefox\firefox.exe
C:\Programmi\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 = http://www.libero.it/
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 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Programmi\Java\jre6\bin\jp2ssv.dll
O2 - BHO: JQSIEStartDetectorImpl - {E7E6F031-17CE-4C07-BC86-EABFE594F69C} - C:\Programmi\Java\jre6\lib\deploy\jqs\ie\jqs_plugin.dll
O4 - HKLM\..\Run: [COMODO Firewall Pro] "C:\Programmi\COMODO\Firewall\cfp.exe" -h
O4 - HKLM\..\Run: [avgnt] "C:\Programmi\Avira\AntiVir PersonalEdition Classic\avgnt.exe" /min /nosplash
O4 - HKLM\..\Run: [CnxTrApp] rundll32.exe "C:\Programmi\StarModem\StarModem USB Network\CnxTrApp.dll",AppEntry -REG "Conexant\Conexant USB Network"
O4 - HKLM\..\Run: [PCSuiteTrayApplication] C:\PROGRA~1\Nokia\Nokia PC Suite 6\LaunchApplication.exe -startup
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Programmi\Java\jre6\bin\jusched.exe"
O4 - HKLM\..\Run: [Malwarebytes' Anti-Malware] "C:\Programmi\Malwarebytes' Anti-Malware\mbamgui.exe" /starttray
O4 - HKLM\..\Run: [COMODO Internet Security] "C:\Programmi\COMODO\Firewall\cfp.exe" -h
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 - Startup: ERUNT AutoBackup.lnk = C:\Programmi\ERUNT\AUTOBACK.EXE
O9 - Extra button: Ricerche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MI1933~1\OFFICE11\REFIEBAR.DLL
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Programmi\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Programmi\Messenger\msmsgs.exe
O16 - DPF: {0E5F0222-96B9-11D3-8997-00104BD12D94} (PCPitstop Utility) - http://www.pcpitstop.com/pcpitstop/PCPitStop.CAB
O23 - Service: a-squared Free Service (a2free) - Emsi Software GmbH - C:\Programmi\a-squared Free\a2service.exe
O23 - Service: Avira AntiVir Personal - Free Antivirus Scheduler (AntiVirScheduler) - Avira GmbH - C:\Programmi\Avira\AntiVir PersonalEdition Classic\sched.exe
O23 - Service: Avira AntiVir Personal - Free Antivirus Guard (AntiVirService) - Avira GmbH - C:\Programmi\Avira\AntiVir PersonalEdition Classic\avguard.exe
O23 - Service: COMODO Internet Security Helper Service (cmdAgent) - Unknown owner - C:\Programmi\COMODO\Firewall\cmdagent.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Programmi\Java\jre6\bin\jqs.exe
O23 - Service: MBAMService - Malwarebytes Corporation - C:\Programmi\Malwarebytes' Anti-Malware\mbamservice.exe
O23 - Service: O&O Defrag - O&O Software GmbH - C:\WINDOWS\system32\oodag.exe
O23 - Service: ServiceLayer - Nokia. - C:\Programmi\File comuni\PCSuite\Services\ServiceLayer.exe

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End of file - 4819 bytes grazie tante

dalla scansione ho visto che hai il malwarebytes, hai fatto una scansione completa? se si, non ha trovato nulla?

il log è quello che il programma fa uscire tu dici che non è completo? per quanto riguarda l'sp3 non ho ancora deciso se installarlo oppure no sono molto indeciso......... si ho fatto una scansione completa con malwarebytes e non ha trovato nulla che sarà mai?