my system got infected with the BDU/small.iuj virus. it infected the explorer.exe file. so i quarantined the file and i lost all my desktop icons and the start button. registry fixes don't work so i just restored the explorer.exe file. is there any way we can remove the virus from infecting those files?

hijackthis log:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 1:06:13 AM, on 2/13/2010
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)
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:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Avira\AntiVir Desktop\sched.exe
C:\Program Files\Avira\AntiVir Desktop\avguard.exe
C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
C:\Program Files\Bonjour\mDNSResponder.exe
C:\Program Files\Java\jre6\bin\jqs.exe
C:\Program Files\Yahoo!\SoftwareUpdate\YahooAUService.exe
C:\WINDOWS\system32\rundll32.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\WINDOWS\system32\taskmgr.exe
C:\Program Files\Avira\AntiVir Desktop\avscan.exe
C:\WINDOWS\explorer.exe
C:\Program Files\Avira\AntiVir Desktop\avgnt.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Program Files\iTunes\iTunesHelper.exe
C:\Program Files\Autorun Eater\oldmcdonald.exe
C:\Program Files\Yahoo!\Search Protection\SearchProtection.exe
C:\Program Files\MSN Messenger\msnmsgr.exe
C:\Program Files\Autorun Eater\billy.exe
C:\Program Files\iPod\bin\iPodService.exe
C:\PROGRA~1\Yahoo!\MESSEN~1\ymsgr_tray.exe
C:\WINDOWS\system32\mmc.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://aa.rd.yahoo.com/customize/ie/defaults/sp/msgr9/*http://ph.yahoo.com
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.facebook.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://aa.rd.yahoo.com/customize/ie/defaults/su/msgr9/*http://ph.yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://aa.rd.yahoo.com/customize/ie/defaults/sp/msgr9/*http://ph.yahoo.com
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://search.live.com/sphome.aspx
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://aa.rd.yahoo.com/customize/ie/defaults/su/msgr9/*http://ph.yahoo.com
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Service Pack 3 Internet Explorer
R3 - URLSearchHook: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\PROGRA~1\YAHOO!\Companion\Installs\cpn\yt.dll
O2 - BHO: &Yahoo! Toolbar Helper - {02478D38-C3F9-4efb-9B51-7695ECA05670} - C:\PROGRA~1\YAHOO!\Companion\Installs\cpn\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) - {5C255C8A-E604-49b4-9D64-90988571CECB} - (no file)
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre6\bin\jp2ssv.dll
O2 - BHO: JQSIEStartDetectorImpl - {E7E6F031-17CE-4C07-BC86-EABFE594F69C} - C:\Program Files\Java\jre6\lib\deploy\jqs\ie\jqs_plugin.dll
O2 - BHO: SingleInstance Class - {FDAD4DA1-61A2-4FD8-9C17-86F7AC245081} - C:\PROGRA~1\YAHOO!\Companion\Installs\cpn\YTSingleInstance.dll
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\PROGRA~1\YAHOO!\Companion\Installs\cpn\yt.dll
O4 - HKLM\..\Run: [avgnt] "C:\Program Files\Avira\AntiVir Desktop\avgnt.exe" /min
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime Alternative\qttask.exe" -atboottime
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKLM\..\Run: [Autorun Eater] C:\Program Files\Autorun Eater\oldmcdonald.exe
O4 - HKCU\..\Run: [Messenger (Yahoo!)] "C:\PROGRA~1\Yahoo!\MESSEN~1\YAHOOM~1.EXE" -quiet
O4 - HKCU\..\Run: [Search Protection] C:\Program Files\Yahoo!\Search Protection\SearchProtection.exe
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\MSN Messenger\msnmsgr.exe" /background
O4 - HKUS\S-1-5-19\..\Run: [msnsc] C:\WINDOWS\system32\msnsc.exe (User 'LOCAL SERVICE')
O4 - HKUS\S-1-5-19\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'LOCAL SERVICE')
O4 - HKUS\S-1-5-20\..\Run: [msnsc] C:\WINDOWS\system32\msnsc.exe (User 'NETWORK SERVICE')
O4 - HKUS\S-1-5-20\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'NETWORK SERVICE')
O4 - HKUS\S-1-5-18\..\Run: [msnsc] C:\WINDOWS\system32\msnsc.exe (User 'SYSTEM')
O4 - HKUS\S-1-5-18\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [msnsc] C:\WINDOWS\system32\msnsc.exe (User 'Default user')
O4 - HKUS\.DEFAULT\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'Default user')
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~1\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~1\OFFICE11\REFIEBAR.DLL
O16 - DPF: {6D2EF4B4-CB62-4C0B-85F3-B79C236D702C} (ContactExtractor Class) - http://www.facebook.com/controls/contactx.dll
O23 - Service: Avira AntiVir Scheduler (AntiVirSchedulerService) - Avira GmbH - C:\Program Files\Avira\AntiVir Desktop\sched.exe
O23 - Service: Avira AntiVir Guard (AntiVirService) - Avira GmbH - C:\Program Files\Avira\AntiVir Desktop\avguard.exe
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
O23 - Service: Bonjour Service - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Program Files\Java\jre6\bin\jqs.exe
O23 - Service: Yahoo! Updater (YahooAUService) - Yahoo! Inc. - C:\Program Files\Yahoo!\SoftwareUpdate\YahooAUService.exe

--
End of file - 6280 bytes

Please visit this webpage for a tutorial on downloading and running ComboFix:

http://www.bleepingcomputer.com/combofix/how-to-use-combofix

See the area: Using ComboFix, and when done, post the log back here.