I did all what you said (i.e. run mwav scan, Spybot S&D program, Adware, VX2 cleaner and also the Cwschredder - the last two did not find anything) and here is the new Hijackthis log. It seems that at least WinAdCtl and WinAdAlt are still there. Is it possible to get rid of them? Is there anything else strange in the logfile?
O2 - BHO: SpywareGuard Download Protection - {4A368E80-174F-4872-96B5-0B27DDD11DB2} - C:\Program Files\SpywareGuard\dlprotect.dll
O2 - BHO: NAV Helper - {BDF3E430-B101-42AD-A544-FADC6B084872} - C:\Program Files\Norton AntiVirus\NavShExt.dll
O3 - Toolbar: Norton AntiVirus - {42CDD1BF-3FFB-4238-8AD1-7859DF00B1D6} - C:\Program Files\Norton AntiVirus\NavShExt.dll
O4 - HKLM\..\Run: [CTSysVol] C:\Program Files\Creative\SBAudigy2\Surround Mixer\CTSysVol.exe
O4 - HKLM\..\Run: [CTDVDDet] C:\Program Files\Creative\SBAudigy2\DVDAudio\CTDVDDet.EXE
O4 - HKLM\..\Run: [CTHelper] CTHELPER.EXE
O4 - HKLM\..\Run: [AsioReg] REGSVR32.EXE /S CTASIO.DLL
O4 - HKLM\..\Run: [SBDrvDet] C:\Program Files\Creative\SB Drive Det\SBDrvDet.exe /r
O4 - HKLM\..\Run: [UpdReg] C:\WINDOWS\UpdReg.EXE
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\System32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [zBrowser Launcher] C:\Program Files\Logitech\iTouch\iTouch.exe
O4 - HKLM\..\Run: [Logitech Utility] Logi_MwX.Exe
O4 - HKLM\..\Run: [NeroCheck] C:\WINDOWS\System32\\NeroCheck.exe
O4 - HKLM\..\Run: [InCD] C:\Program Files\Ahead\InCD\InCD.exe
O4 - HKLM\..\Run: [ccApp] "C:\Program Files\Common Files\Symantec Shared\ccApp.exe"
O4 - HKLM\..\Run: [Zone Labs Client] "C:\Program Files\Zone Labs\ZoneAlarm\zlclient.exe"
O4 - HKLM\..\Run: [Windows AdControl] C:\Program Files\Windows AdControl\WinAdCtl.exe
O4 - HKLM\..\Run: [tkjlpynesolq] C:\WINDOWS\system32\ldiwmm.exe
O4 - HKCU\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\System32\NVMCTRAY.DLL,NvTaskbarInit
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - Startup: SpywareGuard.lnk = C:\Program Files\SpywareGuard\sgmain.exe
O4 - Global Startup: hp psc 1000 series.lnk = ?
O4 - Global Startup: hpoddt01.exe.lnk = ?
O8 - Extra context menu item: E&xportar a Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Referencia - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O16 - DPF: ppctlcab -
http://www.pestscan.com/scanner/ppctlcab.cabO16 - DPF: {2359626E-7524-4F87-B04E-22CD38A0C88C} (ICSScannerLight Class) -
http://download.zonelabs.com/bin/free/cm/ICSCM.cabO16 - DPF: {2FC9A21E-2069-4E47-8235-36318989DB13} (PPSDKActiveXScanner.MainScreen) -
http://www.pestscan.com/scanner/axscanner.cabO16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) -
http://v5.windowsupdate.microsoft.com/v5consumer/V5Controls/en/x86/client/wuweb_site.cab?1100159074234