Logfile of HijackThis v1.99.1
Scan saved at 19.34.08, on 22/03/2006
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\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\PROGRA~1\Grisoft\AVGFRE~1\avgamsvr.exe
C:\PROGRA~1\Grisoft\AVGFRE~1\avgupsvc.exe
C:\Programmi\File comuni\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\WINDOWS\Explorer.EXE
C:\Programmi\Analog Devices\SoundMAX\SMAgent.exe
C:\WINDOWS\System32\PAStiSvc.exe
C:\WINDOWS\system32\svchost.exe
C:\PROGRA~1\Grisoft\AVGFRE~1\avgcc.exe
C:\PROGRA~1\Grisoft\AVGFRE~1\avgemc.exe
C:\Programmi\QuickTime\qttask.exe
C:\Programmi\Analog Devices\SoundMAX\SMTray.exe
C:\WINDOWS\sm56hlpr.exe
C:\Programmi\Java\jre1.5.0_06\bin\jusched.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programmi\Messenger\msmsgs.exe
C:\Programmi\Skype\Phone\Skype.exe
C:\Programmi\Digisoft AntiDialer\AntiDialer.exe
C:\Programmi\Ulead Systems\Ulead Photo Express 3.0 SE\CalCheck.exe
C:\PROGRA~1\INCRED~1\bin\IMApp.exe
C:\Programmi\Internet Explorer\iexplore.exe
C:\Programmi\File comuni\Microsoft Shared\Encarta Web Companion\ENCWCSVR.EXE
C:\Programmi\a2 Free\a2start.exe
C:\Programmi\a2 Free\a2upd.exe
C:\Programmi\MSN Messenger\msnmsgr.exe
C:\Documents and Settings\Administrator\Desktop\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.msn.it/
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: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Programmi\Java\jre1.5.0_06\bin\ssv.dll
O2 - BHO: Encarta Web Companion Oggetto helper - {955BE0B8-BC85-4CAF-856E-8E0D8B610560} - C:\Programmi\File comuni\Microsoft Shared\Encarta Web Companion\ENCWCBAR.DLL
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - c:\programmi\google\googletoolbar2.dll
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Programmi\Yahoo!\Companion\Installs\cpn\yt.dll
O3 - Toolbar: &Google - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - c:\programmi\google\googletoolbar2.dll
O3 - Toolbar: Encarta Web Companion - {147D6308-0614-4112-89B1-31402F9B82C4} - C:\Programmi\File comuni\Microsoft Shared\Encarta Web Companion\ENCWCBAR.DLL
O4 - HKLM\..\Run: [AVG7_CC] C:\PROGRA~1\Grisoft\AVGFRE~1\avgcc.exe /STARTUP
O4 - HKLM\..\Run: [AVG7_EMC] C:\PROGRA~1\Grisoft\AVGFRE~1\avgemc.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Programmi\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [NeroFilterCheck] C:\WINDOWS\system32\NeroCheck.exe
O4 - HKLM\..\Run: [Smapp] C:\Programmi\Analog Devices\SoundMAX\SMTray.exe
O4 - HKLM\..\Run: [SMSERIAL] sm56hlpr.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Programmi\Java\jre1.5.0_06\bin\jusched.exe
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [IncrediMail] C:\Programmi\IncrediMail\bin\IncMail.exe /c
O4 - HKCU\..\Run: [MSMSGS] "C:\Programmi\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [Skype] "C:\Programmi\Skype\Phone\Skype.exe" /nosplash /minimized
O4 - Global Startup: Adobe Gamma Loader.lnk = C:\Programmi\File comuni\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Global Startup: Avvio veloce di Adobe Reader.lnk = C:\Programmi\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Digisoft AntiDialer.lnk = C:\Programmi\Digisoft AntiDialer\AntiDialer.exe
O4 - Global Startup: Ulead Photo Express SE Calendar Checker.lnk = C:\Programmi\Ulead Systems\Ulead Photo Express 3.0 SE\CalCheck.exe
O8 - Extra context menu item: &Add animation to IncrediMail Style Box - C:\PROGRA~1\INCRED~1\bin\resources\WebMenuImg.htm
O8 - Extra context menu item: &Google Search - res://c:\programmi\google\GoogleToolbar2.dll/cmsearch.html
O8 - Extra context menu item: &Translate English Word - res://c:\programmi\google\GoogleToolbar2.dll/cmwordtrans.html
O8 - Extra context menu item: Backward Links - res://c:\programmi\google\GoogleToolbar2.dll/cmbacklinks.html
O8 - Extra context menu item: Cached Snapshot of Page - res://c:\programmi\google\GoogleToolbar2.dll/cmcache.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: Similar Pages - res://c:\programmi\google\GoogleToolbar2.dll/cmsimilar.html
O8 - Extra context menu item: Translate Page into English - res://c:\programmi\google\GoogleToolbar2.dll/cmtrans.html
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Programmi\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Programmi\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra button: Ricerche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: (no name) - {B205A35E-1FC4-4CE3-818B-899DBBB3388C} - C:\Programmi\File comuni\Microsoft Shared\Encarta Search Bar\ENCSBAR.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: {00B71CFB-6864-4346-A978-C0A14556272C} (Checkers Class) - http://messenger.zone.msn.com/binary/msgrchkr.cab31267.cab
O16 - DPF: {14B87622-7E19-4EA8-93B3-97215F77A6BC} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsPAClient.cab31267.cab
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://update.microsoft.com/windowsupdate/v6/V5Controls/en/x86/client/wuweb_site.cab?1128432338484
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsClient.cab31267.cab
O16 - DPF: {B38870E4-7ECB-40DA-8C6A-595F0A5519FF} (MsnMessengerSetupDownloadControl Class) - http://messenger.msn.com/download/MsnMessengerSetupDownloader.cab
O16 - DPF: {B8BE5E93-A60C-4D26-A2DC-220313175592} (ZoneIntro Class) - http://messenger.zone.msn.com/binary/ZIntro.cab32846.cab
O16 - DPF: {F6BF0D00-0B2A-4A75-BF7B-F385591623AF} (Solitaire Showdown Class) - http://messenger.zone.msn.com/binary/SolitaireShowdown.cab31267.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{C085C189-FBDB-4BA1-954B-B3966AA50B0C}: NameServer = 192.168.0.1
O17 - HKLM\System\CCS\Services\Tcpip\..\{C9CAD680-2CFE-4613-803F-306E24BA56A9}: NameServer = 193.70.152.25 193.70.192.25
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - "C:\PROGRA~1\MSNMES~1\msgrapp.dll" (file missing)
O23 - Service: AVG7 Alert Manager Server (Avg7Alrt) - GRISOFT, s.r.o. - C:\PROGRA~1\Grisoft\AVGFRE~1\avgamsvr.exe
O23 - Service: AVG7 Update Service (Avg7UpdSvc) - GRISOFT, s.r.o. - C:\PROGRA~1\Grisoft\AVGFRE~1\avgupsvc.exe
O23 - Service: SoundMAX Agent Service (SoundMAX Agent Service (default)) - Analog Devices, Inc. - C:\Programmi\Analog Devices\SoundMAX\SMAgent.exe
O23 - Service: STI Simulator - Unknown owner - C:\WINDOWS\System32\PAStiSvc.exe

L'unica cosa che ti posso dire che dal tuo log risulta che ti manca un firewall ,vai qui' leggi e scarica http://www.aiutamici.com/software/descrizione.asp?CodSw=56.
che problemi riscontri?