my problem started yesterday when somebody used my pc & when it my time to used my pc the home page of my internet explorer won't changed back to it default home page. so i search the web & found it as a spyware. i scan it with hijack this and the log is as follows;
Logfile of HijackThis v1.99.1
Scan saved at 11:49:43 PM, on 10/5/2006
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\RTHDCPL.EXE
C:\PROGRA~1\Grisoft\AVGFRE~1\avgcc.exe
C:\Program Files\D-Tools\daemon.exe
C:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
C:\Program Files\Yahoo!\Messenger\ymsgr_tray.exe
C:\PROGRA~1\Grisoft\AVGFRE~1\avgamsvr.exe
C:\PROGRA~1\Grisoft\AVGFRE~1\avgupsvc.exe
C:\PROGRA~1\Grisoft\AVGFRE~1\avgemc.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\system32\wuauclt.exe
C:\WINDOWS\system32\wscntfy.exe
C:\DOCUME~1\User6\LOCALS~1\Temp\Temporary Directory 2 for hijackthis.zip\HijackThis.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\PROGRA~1\Yahoo!\COMPAN~1\Installs\cpn0\YTBSDK.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://us.rd.yahoo.com/customize/ycomp/def…/search/ie.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://us.rd.yahoo.com/customize/ycomp/def…//www.yahoo.com
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://quatangtraitim.us.tf/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.yahoo.com
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.yahoo.com
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://us.rd.yahoo.com/customize/ycomp/def…//www.yahoo.com
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Qua Tang Trai Tim http://quatangtraitim.us.tf
R3 - URLSearchHook: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O2 - BHO: Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: Yahoo! IE Services Button - {5BAB4B5B-68BC-4B02-94D6-2FC0DE4A7897} - C:\Program Files\Yahoo!\Common\yiesrvc.dll
O3 - Toolbar: Easy-WebPrint - {327C2873-E90D-4c37-AA9D-10AC9BABA46C} - C:\Program Files\Canon\Easy-WebPrint\Toolband.dll
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O4 - HKLM\..\Run: [RTHDCPL] RTHDCPL.EXE
O4 - HKLM\..\Run: [Alcmtr] ALCMTR.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: [AVG7_CC] C:\PROGRA~1\Grisoft\AVGFRE~1\avgcc.exe /STARTUP
O4 - HKLM\..\Run: [DAEMON Tools-1033] "C:\Program Files\D-Tools\daemon.exe" -lang 1033
O4 - HKLM\..\Run: [Easy-PrintToolBox] C:\Program Files\Canon\Easy-PrintToolBox\BJPSMAIN.EXE /logon
O4 - HKCU\..\Run: [Yahoo! Pager] C:\Program Files\Yahoo!\Messenger\ypager.exe -quiet
O4 - Global Startup: Adobe Reader Speed Launch.lnk = C:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O6 - HKCU\Software\Policies\Microsoft\Internet Explorer\Control Panel present
O8 - Extra context menu item: &Yahoo! Search - file:///C:\Program Files\Yahoo!\Common/ycsrch.htm
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O8 - Extra context menu item: Easy-WebPrint Add To Print List - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_AddToList.html
O8 - Extra context menu item: Easy-WebPrint High Speed Print - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_HSPrint.html
O8 - Extra context menu item: Easy-WebPrint Preview - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_Preview.html
O8 - Extra context menu item: Easy-WebPrint Print - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_Print.html
O8 - Extra context menu item: Yahoo! &Dictionary - file:///C:\Program Files\Yahoo!\Common/ycdict.htm
O8 - Extra context menu item: Yahoo! &Maps - file:///C:\Program Files\Yahoo!\Common/ycmap.htm
O8 - Extra context menu item: Yahoo! &SMS - file:///C:\Program Files\Yahoo!\Common/ycsms.htm
O9 - Extra button: Yahoo! Services - {5BAB4B5B-68BC-4B02-94D6-2FC0DE4A7897} - C:\Program Files\Yahoo!\Common\yiesrvc.dll
O9 - Extra button: Research - {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: {30528230-99f7-4bb4-88d8-fa1d4f56a2ab} (YInstStarter Class) - C:\Program Files\Yahoo!\Common\yinsthelper.dll
O23 - Service: AVG7 Alert Manager Server (Avg7Alrt) - GRISOFT, s.r.o. - C:\PROGRA~1\Grisoft\AVGFRE~1\avgamsvr.exe
O23 - Service: AVG7 Update Service (Avg7UpdSvc) - GRISOFT, s.r.o. - C:\PROGRA~1\Grisoft\AVGFRE~1\avgupsvc.exe
O23 - Service: AVG E-mail Scanner (AVGEMS) - GRISOFT, s.r.o. - C:\PROGRA~1\Grisoft\AVGFRE~1\avgemc.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe

what should i do, will somebody help me, please