ogni tanto come accendo il pc mi compare una finestra con un errore in quella libreria come posso risolvere? grazie di tutto<img src="http://img220.imageshack.us/img220/8665/immagine3yz7.th.png" border=0>

fai un attento controllo della libreria che deve soddisfare questi requisiti:

http://www.file.net/process/rundll32.exe.html

altrimenti potrebbe trattarsi di un virus.

per intanto cerca rundll.exe e individua il percorso di allocazione...
se tutto è a posto deve trovarsi in C:\Windows\System32 ed essere delle dimensioni indicate alla voce "description"

la domanda è sono tutti leciti?

in merito a questo errore vi post il Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 15.18.27, on 25/09/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16512)
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:\Programmi\Sygate\SPF\smc.exe
C:\Programmi\Alwil Software\Avast4\aswUpdSv.exe
C:\Programmi\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\rundll32.exe
C:\PROGRA~1\ALWILS~2\Avast4\ashDisp.exe
C:\Programmi\Advanced Registry Doctor\RegManServ.exe
C:\WINDOWS\system32\svchost.exe
C:\Programmi\Alwil Software\Avast4\ashMaiSv.exe
C:\Programmi\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\System32\taskmgr.exe
C:\Programmi\Acoo Browser\AcooBrowser.exe
C:\Programmi\hijackthis\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://g.msn.it/0SEITIT/SAOS01?FORM=TOOLBR
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://g.msn.it/0SEITIT/SAOS01?FORM=TOOLBR
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
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://g.msn.it/0SEITIT/SAOS01?FORM=TOOLBR
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: Supporto di collegamento per Adobe PDF Reader - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Programmi\File comuni\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {206E52E0-D52E-11D4-AD54-0000E86C26F6} - C:\Programmi\FreshDevices\FreshDownload\FDCatch.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Programmi\Java\jre1.6.0_01\bin\ssv.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Programmi\File comuni\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O3 - Toolbar: FreshDownload Bar - {ED0E8CA5-42FB-4B18-997B-769E0408E79D} - C:\Programmi\FreshDevices\FreshDownload\fdiebar.dll
O4 - HKLM\..\Run: [CnxTrApp] rundll32.exe "C:\Programmi\StarModem\StarModem USB Network\CnxTrApp.dll",AppEntry -REG "Conexant\Conexant USB Network"
O4 - HKLM\..\Run: [SmcService] C:\PROGRA~1\Sygate\SPF\smc.exe -startgui
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~2\Avast4\ashDisp.exe
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVIZIO DI RETE')
O4 - HKUS\S-1-5-18\..\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
O6 - HKCU\Software\Policies\Microsoft\Internet Explorer\Toolbars\Restrictions present
O8 - Extra context menu item: Add to Windows &Live Favorites - http://favorites.live.com/quickadd.aspx
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Programmi\Java\jre1.6.0_01\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Programmi\Java\jre1.6.0_01\bin\ssv.dll
O9 - Extra button: FreshDownload - {2897A555-C2D4-4F6E-9714-452C13925807} - C:\Programmi\FreshDevices\FreshDownload\fd.exe
O9 - Extra button: Ricerche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\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: {2BC66F54-93A8-11D3-BEB6-00105AA9B6AE} (Symantec AntiVirus scanner) - http://security.symantec.com/sscv6/SharedContent/vc/bin/AvSniff.cab
O16 - DPF: {4F1E5B1A-2A80-42CA-8532-2D05CB959537} (MSN Photo Upload Tool) - http://mukka1989.spaces.live.com//PhotoUpload/MsnPUpld.cab
O16 - DPF: {5D6F45B3-9043-443D-A792-115447494D24} (UnoCtrl Class) - http://messenger.zone.msn.com/IT-IT/a-UNO1/GAME_UNO1.cab
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://update.microsoft.com/windowsupdate/v6/V5Controls/en/x86/client/wuweb_site.cab?1165010330765
O16 - DPF: {644E432F-49D3-41A1-8DD5-E099162EEEC5} (Symantec RuFSI Utility Class) - http://security.symantec.com/sscv6/SharedContent/common/bin/cabsa.cab
O16 - DPF: {7FC1B346-83E6-4774-8D20-1A6B09B0E737} (Windows Live Photo Upload Control) - http://gio101089.spaces.live.com/PhotoUpload/MsnPUpld.cab
O16 - DPF: {8436FE12-31DB-48BF-83BF-FE682F9160B4} (NanoInstaller Class) - http://www.nanoscan.com/cabs/nanoinst.cab
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsClient.cab31267.cab
O16 - DPF: {9A9307A0-7DA4-4DAF-B042-5009F29E09E1} - http://www.nanoscan.com/as/v1/cabs/asinst.cab
O16 - DPF: {C3F79A2B-B9B4-4A66-B012-3EE46475B072} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsPAClient.cab56907.cab
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Programmi\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: avast! Antivirus - ALWIL Software - C:\Programmi\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Mail Scanner - ALWIL Software - C:\Programmi\Alwil Software\Avast4\ashMaiSv.exe
O23 - Service: avast! Web Scanner - ALWIL Software - C:\Programmi\Alwil Software\Avast4\ashWebSv.exe
O23 - Service: Registry Management Service (RegManServ) - Unknown owner - C:\Programmi\Advanced Registry Doctor\RegManServ.exe
O23 - Service: Sygate Personal Firewall (SmcService) - Sygate Technologies, Inc. - C:\Programmi\Sygate\SPF\smc.exe

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End of file - 6698 bytes
grazie ma se mi rispondete è meglio.