Ciao! Ho fatto uno scan con Malwarebytes e mi ha trovato vundo.h. Ho lanciato hijackthis e questo è il risultato:
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 14.25.23, on 31/01/2009
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16762)
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\Alwil Software\Avast4\aswUpdSv.exe
C:\Programmi\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\RTHDCPL.EXE
C:\Program Files\ASUS\Six Engine\SixEngine.exe
C:\Programmi\I-Storm USB ADSL Modem\CnxDslTb.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\Programmi\Java\jre1.5.0_04\bin\jusched.exe
C:\WINDOWS\system32\PnkBstrA.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\RUNDLL32.EXE
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programmi\Logitech\MouseWare\system\em_exec.exe
C:\Programmi\Windows Live\Messenger\MsnMsgr.Exe
C:\documents and settings\elyyyx\impostazioni locali\dati applicazioni\mkqwnt.exe
C:\Programmi\Adobe\Acrobat 7.0\Reader\reader_sl.exe
C:\WINDOWS\system32\wscntfy.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Programmi\Internet Explorer\iexplore.exe
C:\Programmi\Windows Live\Messenger\usnsvc.exe
C:\Programmi\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://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 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
O2 - BHO: (no name) - {02478D38-C3F9-4efb-9B51-7695ECA05670} - (no file)
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) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: FDMIECookiesBHO Class - {CC59E0F9-7E43-44FA-9FAA-8377850BF205} - C:\Programmi\Free Download Manager\iefdm2.dll
O4 - HKLM\..\Run: [RTHDCPL] RTHDCPL.EXE
O4 - HKLM\..\Run: [Alcmtr] ALCMTR.EXE
O4 - HKLM\..\Run: [Six Engine] "C:\Program Files\ASUS\Six Engine\SixEngine.exe" -r
O4 - HKLM\..\Run: [CnxDslTaskBar] "C:\Programmi\I-Storm USB ADSL Modem\CnxDslTb.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Programmi\Java\jre1.5.0_04\bin\jusched.exe
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [HPLJ Config] C:\Programmi\Hewlett-Packard\hp LaserJet 1010 Series\SetConfig.exe -c Direct -p USB -pn "hp LJ 1010 Series - 2 Driver" -n 0 -l 1040 -sl 120000
O4 - HKLM\..\Run: [Logitech Utility] Logi_MwX.Exe
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [DAEMON Tools] "C:\Programmi\DAEMON Tools\daemon.exe" -lang 1033
O4 - HKCU\..\Run: [MsnMsgr] "C:\Programmi\Windows Live\Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [Messenger (Yahoo!)] "C:\Programmi\Yahoo!\Messenger\YahooMessenger.exe" -quiet
O4 - HKCU\..\Run: [Skype] "C:\Programmi\Skype\Phone\Skype.exe" /nosplash /minimized
O4 - HKCU\..\Run: [Antispyware] C:\Programmi\Antispyware\Antispyware.exe -boot
O4 - HKCU\..\Run: [kamsoft] C:\WINDOWS\system32\kamsoft.exe
O4 - HKCU\..\Run: [mkqwnt] "c:\documents and settings\elyyyx\impostazioni locali\dati applicazioni\mkqwnt.exe" mkqwnt
O4 - HKCU\..\Run: [Free Download Manager] "C:\Programmi\Free Download Manager\fdm.exe" -autorun
O4 - HKCU\..\Run: [cdoosoft] C:\WINDOWS\system32\olhrwef.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 - Global Startup: Adobe Reader Speed Launch.lnk = C:\Programmi\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Tasto di scelta rapida per l'avvio di AutoCAD.lnk = C:\Programmi\File comuni\Autodesk Shared\acstart17.exe
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
O8 - Extra context menu item: Scarica con Free Download Manager - file://C:\Programmi\Free Download Manager\dllink.htm
O8 - Extra context menu item: Scarica i video con Free Download Manager - file://C:\Programmi\Free Download Manager\dlfvideo.htm
O8 - Extra context menu item: Scarica selezionati con Free Download Manager - file://C:\Programmi\Free Download Manager\dlselected.htm
O8 - Extra context menu item: Scarica tutto con Free Download Manager - file://C:\Programmi\Free Download Manager\dlall.htm
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Programmi\Java\jre1.5.0_04\bin\npjpi150_04.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Programmi\Java\jre1.5.0_04\bin\npjpi150_04.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
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
O10 - Unknown file in Winsock LSP: c:\windows\system32\nwprovau.dll
O15 - Trusted Zone: http://asia.msi.com.tw
O15 - Trusted Zone: http://global.msi.com.tw
O15 - Trusted Zone: http://www.msi.com.tw
O16 - DPF: {17492023-C23A-453E-A040-C7C580BBF700} (Windows Genuine Advantage Validation Tool) - http://go.microsoft.com/fwlink/?linkid=39204
O16 - DPF: {1A781DED-C22D-4153-3213-A3211E29DF13} (GameDesire Card Games) - http://194.244.16.117/g_bin/eng/cards_2_0_0_77.cab
O16 - DPF: {20A60F0D-9AFA-4515-A0FD-83BD84642501} (Checkers Class) - http://messenger.zone.msn.com/binary/msgrchkr.cab56986.cab
O16 - DPF: {5D6F45B3-9043-443D-A792-115447494D24} (UnoCtrl Class) - http://messenger.zone.msn.com/IT-IT/a-UNO1/GAME_UNO1.cab
O16 - DPF: {8167C273-DF59-4416-B647-C8BB2C7EE83E} (WebSDev Control) - http://liveupdate.msi.com.tw/autobios/LOnline/install.cab
O16 - DPF: {C3F79A2B-B9B4-4A66-B012-3EE46475B072} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsPAClient.cab56907.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{B27D777F-92D7-4B60-AA1A-F6A7847CBBBC}: NameServer = 193.12.150.2 212.247.152.2
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Programmi\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: Autodesk Licensing Service - Autodesk - C:\Programmi\File comuni\Autodesk Shared\Service\AdskScSrv.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: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Programmi\File comuni\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: Pml Driver HPZ12 - Unknown owner - C:\WINDOWS\system32\HPZipm12.exe (file missing)
O23 - Service: PnkBstrA - Unknown owner - C:\WINDOWS\system32\PnkBstrA.exe

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End of file - 8373 bytes

ma il malwarebytes non te l'ha rimosso il vundo? l'ha messo nella quarantena? per eliminare alcune versioni di vundo puoi usare il tool di avast che puoi prendere dal sito ufficiale di avast, e' molto semplice da usare, oppure con il vundofix versione 6.6.2

Ciao.
Importante: Disabilita il tuo antivirus e chiudi TUTTI i programmi aperti,e dopo aver scaricato COMBOFIX, chiudi la connessione.

Scarica Combofix
http://download.bleepingcomputer.com/sUBs/ComboFix.exe
Salvalo sul desktop.
Doppio click su combofix.exe (comparirà una videata.)
Se ti verrà chiesto se vuoi Installare LA CONSOLE DI RIPRISTINO DI EMERGENZA, clicca NO.
Digita 1 premi Invio e segui le indicazioni.
Al termine, verrà creato un file log chiamato C:\ComboFix.txt. Postalo qui.
Durante l'operazione di scansione è importante non usare il PC (neanche il mouse) e attendere pazientemente la fine delle operazioni.

Disinstalla combofix in questo modo: (dopo che avrò visto il log)
Start
Esegui
nella finestra di dialogo, digita (oppure, copia ed incolla) questo comando: Combofix /u e premi invio poi cancella le cartelle in "C" di combofix (qoobox)

Poi posta un log aggiornato di HJT.