I had tried various methods given by other forum but seems useless for me.
Please forgive me as I'm really a computer idiot..

Regards.
Logfile of HijackThis v1.99.1
Scan saved at 1:36:14 PM, on 11/17/2005
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:\WINDOWS\Explorer.exe
C:\WINDOWS\services.exe
C:\Program Files\Common Files\Autodesk Shared\Service\AdskScSrv.exe
C:\Program Files\AVPersonal\AVWUPSRV.EXE
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\RTHDCPL.EXE
C:\Program Files\CyberLink\PowerDVD\PDVDServ.exe
D:\Program Files\iTunes\iTunesHelper.exe
D:\Program Files\Adobe\Photoshop Album Starter Edition\3.0\Apps\apdproxy.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\iPod\bin\iPodService.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Trend Micro\Tmas\Tmas.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\System32\wbem\wmiapsrv.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Hijackthis\HijackThis.exe
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://sg.yahoo.com/
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://sg.yahoo.com/
R3 - Default URLSearchHook is missing
F2 - REG:system.ini: Shell=Explorer.exe C:\WINDOWS\system32\fservice.exe
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - D:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O4 - HKLM\..\Run: [RTHDCPL] RTHDCPL.EXE
O4 - HKLM\..\Run: [Alcmtr] ALCMTR.EXE
O4 - HKLM\..\Run: [AVGCtrl] C:\Program Files\AVPersonal\AVGNT.EXE /min
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [SW20] C:\WINDOWS\system32\sw20.exe
O4 - HKLM\..\Run: [SW24] C:\WINDOWS\system32\sw24.exe
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [RemoteControl] "C:\Program Files\CyberLink\PowerDVD\PDVDServ.exe"
O4 - HKLM\..\Run: [iTunesHelper] "D:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [Adobe Photo Downloader] "D:\Program Files\Adobe\Photoshop Album Starter Edition\3.0\Apps\apdproxy.exe"
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - Startup: Adobe Gamma.lnk = C:\Program Files\Common Files\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Global Startup: Microsoft Office.lnk = C:\Program Files\Microsoft Office\Office10\OSA.EXE
O4 - Global Startup: Adobe Gamma Loader.lnk = C:\Program Files\Common Files\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Global Startup: Adobe Reader Speed Launch.lnk = D:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Trend Micro Anti-Spyware.lnk = C:\Program Files\Trend Micro\Tmas\Tmas.exe
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office10\EXCEL.EXE/3000
O9 - Extra button: Spyware Doctor - {2D663D1A-8670-49D9-A1A5-4C56B4E14E84} - C:\WINDOWS\System32\shdocvw.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: {04E214E5-63AF-4236-83C6-A7ADCBF9BD02} (HouseCall Control) - http://housecall60.t...all/xscan60.cab
O16 - DPF: {17492023-C23A-453E-A040-C7C580BBF700} (Windows Genuine Advantage Validation Tool) - http://go.microsoft....k/?linkid=39204
O16 - DPF: {2917297F-F02B-4B9D-81DF-494B6333150B} (Minesweeper Flags Class) - http://messenger.zon...er.cab31267.cab
O16 - DPF: {62789780-B744-11D0-986B-00609731A21D} (Autodesk MapGuide ActiveX Control) - http://www.can.com.sg/mwf/mgaxctrl.cab
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zon...nt.cab31267.cab
O16 - DPF: {B8BE5E93-A60C-4D26-A2DC-220313175592} (ZoneIntro Class) - http://zone.msn.com/...ro.cab34246.cab
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - "C:\PROGRA~1\MSNMES~1\msgrapp.dll" (file missing)
O23 - Service: Adobe LM Service - Adobe Systems - C:\Program Files\Common Files\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: AntiVir Service (AntiVirService) - H+BEDV Datentechnik GmbH - C:\Program Files\AVPersonal\AVGUARD.EXE
O23 - Service: Autodesk Licensing Service - Unknown owner - C:\Program Files\Common Files\Autodesk Shared\Service\AdskScSrv.exe
O23 - Service: AntiVir Update (AVWUpSrv) - H+BEDV Datentechnik GmbH, Germany - C:\Program Files\AVPersonal\AVWUPSRV.EXE
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: iPodService - Apple Computer, Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe