Logfile of Trend Micro HijackThis v2.0.4
Scan saved at 17.58.00, on 20/05/2010
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v8.00 (8.00.6001.18702)
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:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\Programmi\Avira\AntiVir Desktop\sched.exe
C:\WINDOWS\system32\agrsmsvc.exe
C:\Programmi\Avira\AntiVir Desktop\avguard.exe
C:\Programmi\Java\jre6\bin\jqs.exe
C:\Programmi\File comuni\Microsoft Shared\VS7DEBUG\mdm.exe
C:\WINDOWS\system32\MsPMSPSv.exe
C:\WINDOWS\system32\SearchIndexer.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Programmi\Avira\AntiVir Desktop\avmailc.exe
C:\Programmi\Avira\AntiVir Desktop\AVWEBGRD.EXE
C:\WINDOWS\system32\wbem\wmiapsrv.exe
C:\Programmi\Avira\AntiVir Desktop\avgnt.exe
C:\Programmi\Synaptics\SynTP\SynTPEnh.exe
C:\Programmi\LClock\LClock.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programmi\File comuni\Ahead\Lib\NMBgMonitor.exe
C:\Programmi\File comuni\Ahead\Lib\NMIndexingService.exe
C:\Programmi\File comuni\Ahead\Lib\NMIndexStoreSvr.exe
C:\WINDOWS\system32\SearchProtocolHost.exe
C:\WINDOWS\system32\msiexec.exe
C:\Programmi\Avira\AntiVir Desktop\update.exe
C:\Programmi\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 = http://www.google.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: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Programmi\File comuni\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: (no name) - {5C255C8A-E604-49b4-9D64-90988571CECB} - (no file)
O2 - BHO: Groove GFS Browser Helper - {72853161-30C5-4D22-B7F9-0BBC1D38A37E} - C:\Programmi\Microsoft Office\Office12\GrooveShellExtensions.dll
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: [avgnt] "C:\Programmi\Avira\AntiVir Desktop\avgnt.exe" /min
O4 - HKLM\..\Run: [SynTPEnh] C:\Programmi\Synaptics\SynTP\SynTPEnh.exe
O4 - HKCU\..\Run: [LClock] C:\Programmi\LClock\LClock.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [BgMonitor_{79662E04-7C6C-4d9f-84C7-88D8A56B10AA}] "C:\Programmi\File comuni\Ahead\Lib\NMBgMonitor.exe"
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-19\..\RunOnce: [_nltide_2] regsvr32 /s /n /i:U shell32 (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVIZIO DI RETE')
O4 - HKUS\S-1-5-20\..\RunOnce: [_nltide_2] regsvr32 /s /n /i:U shell32 (User 'SERVIZIO DI RETE')
O4 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\S-1-5-18\..\RunOnce: [_nltide_2] regsvr32 /s /n /i:U shell32 (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'Default user')
O4 - HKUS\.DEFAULT\..\RunOnce: [_nltide_2] regsvr32 /s /n /i:U shell32 (User 'Default user')
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
O9 - Extra button: Invia a OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~1\MICROS~2\Office12\ONBttnIE.dll
O9 - Extra 'Tools' menuitem: I&nvia a OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~1\MICROS~2\Office12\ONBttnIE.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\Office12\REFIEBAR.DLL
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O18 - Protocol: grooveLocalGWS - {88FED34C-F0CA-4636-A375-3CB6248B04CD} - C:\Programmi\Microsoft Office\Office12\GrooveSystemServices.dll
O20 - AppInit_DLLs:
O22 - SharedTaskScheduler: Precaricatore Browseui - {438755C2-A8BA-11D1-B96B-00A0C90312E1} - C:\WINDOWS\system32\browseui.dll
O22 - SharedTaskScheduler: Daemon di cache delle categorie di componenti - {8C7461EF-2B13-11d2-BE35-3078302C2030} - C:\WINDOWS\system32\browseui.dll
O23 - Service: Agere Modem Call Progress Audio (AgereModemAudio) - Agere Systems - C:\WINDOWS\system32\agrsmsvc.exe
O23 - Service: Avira AntiVir MailGuard (AntiVirMailService) - Avira GmbH - C:\Programmi\Avira\AntiVir Desktop\avmailc.exe
O23 - Service: Avira AntiVir Scheduler (AntiVirSchedulerService) - Avira GmbH - C:\Programmi\Avira\AntiVir Desktop\sched.exe
O23 - Service: Avira AntiVir Guard (AntiVirService) - Avira GmbH - C:\Programmi\Avira\AntiVir Desktop\avguard.exe
O23 - Service: Avira AntiVir WebGuard (AntiVirWebService) - Avira GmbH - C:\Programmi\Avira\AntiVir Desktop\AVWEBGRD.EXE
O23 - Service: Com4QLBEx - Hewlett-Packard Development Company, L.P. - C:\Programmi\Hewlett-Packard\HP Quick Launch Buttons\Com4QLBEx.exe
O23 - Service: hpqwmiex - Hewlett-Packard Development Company, L.P. - C:\Programmi\Hewlett-Packard\Shared\hpqwmiex.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Programmi\Java\jre6\bin\jqs.exe
O23 - Service: NBService - Nero AG - C:\Programmi\Nero\Nero 7\Nero BackItUp\NBService.exe
O23 - Service: NMIndexingService - Nero AG - C:\Programmi\File comuni\Ahead\Lib\NMIndexingService.exe

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End of file - 6642 bytes
ecco il log
ciao grazie

Il log è pulito, che problemi hai?

Se hai CCleaner, prova a "disattivare" (da Strumenti\Avvio) tutti i programmi non necessari all'avvio; però attento a non togliere quelli essenziali all'avvio (quelli della Microsoft, dell'ANTIVIRUS-FIREWALL, di eventuali schede audio...).

EDIT: vedo ora che per la stessa cosa hai aperto un'altra discussione.