I have been using Win XP for a couple of months now, having returned to PCs after 4 years of using an Apple Mac!
When I click on a folder to open it, it opens in a new window. Any folders in that one also open in a new window. I cannot seem to change this behaviour, despite changing tools/folder options for the windows, and in control panel.
Clicking to go up a level DOES keep it in the same window, but then clicking on the folder again opens it in a new window! The only way I can prevent a new window opening is to right click on a folder & select open.
Possibly related, I also had a problem recently with all folders opening into a search window - I solved this by going into control panel/folder options. The file type was set to 'find' in Advanced settings. I had to add a new item, browse (and select explorer) , and set it to the default. However, it won't let me edit or remove 'find' or 'browse' - nor indeed any of the file type options at all (I am logged in as the owner, and am the only user of the PC). (SP2 has been installed from the start.)
Any suggestions will be greatfully received, as it's driving me nuts!!!
- As suggested, I've just scanned with Hijack This.

Here's the log:
Logfile of HijackThis v1.99.0
Scan saved at 19:49:27, on 25/12/2004
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\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\McAfee\McAfee Privacy Service\GUARDDOG.EXE
C:\Program Files\Utilities\DKService.exe
c:\PROGRA~1\mcafee.com\vso\mcvsrte.exe
C:\PROGRA~1\McAfee.com\PERSON~1\MPFSERVICE.exe
C:\PROGRA~1\McAfee\SPAMKI~1\MSKSrvr.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\System32\svchost.exe
c:\PROGRA~1\mcafee.com\vso\mcshield.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\McAfee\McAfee Privacy Service\GUARDDOG.EXE
C:\Program Files\Java\j2re1.4.2_03\bin\jusched.exe
C:\windows\system\hpsysdrv.exe
C:\Program Files\HP\hpcoretech\hpcmpmgr.exe
C:\WINDOWS\System32\hphmon05.exe
C:\HP\KBD\KBD.EXE
C:\WINDOWS\AGRSMMSG.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\WINDOWS\ALCWZRD.EXE
C:\WINDOWS\ALCMTR.EXE
C:\Program Files\Thomson\SpeedTouch USB\Dragdiag.exe
C:\PROGRA~1\mcafee.com\agent\mcagent.exe
C:\progra~1\mcafee\spamki~1\mskagent.exe
C:\Program Files\McAfee\McAfee Shared Components\Guardian\CMGrdian.exe
C:\PROGRA~1\mcafee.com\vso\mcvsshld.exe
c:\progra~1\mcafee.com\vso\mcvsescn.exe
C:\PROGRA~1\McAfee.com\PERSON~1\MpfTray.exe
C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
C:\Program Files\Common Files\Real\Update_OB\realsched.exe
C:\Program Files\Aqua Dock\Aqua Dock.exe
C:\Program Files\iTunes\iTunesHelper.exe
C:\Program Files\QuickTime\qttask.exe
C:\Program Files\Messenger\msmsgs.exe
C:\PROGRA~1\McAfee.com\PERSON~1\MpfAgent.exe
C:\PROGRA~1\HPPAVI~1\Pavilion\XPHWWBS4\plugin\bin\pchbutton.exe
C:\Program Files\iPod\bin\iPodService.exe
C:\Program Files\Utilities\Handy Backup 2.1\nhbwp.exe
c:\progra~1\mcafee.com\vso\mcvsftsn.exe
C:\Program Files\HP\Digital Imaging\bin\hpqtra08.exe
C:\Program Files\OpenOffice.org1.1.2\program\soffice.exe
C:\WINDOWS\system32\HPZipm12.exe
C:\Program Files\Adobe\Reader\AcroRd32.exe
C:\Program Files\Utilities\Hijack This\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Bar = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://ie.redirect.hp.com/svs/rdr?TY...ion&pf=desktop
R1 - HKCU\Software\Microsoft\Internet Connection Wizard,ShellNext = http://register.hp.com/servlet/WebRe...J390AA&LF=blue
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Reader\ActiveX\AcroIEHelper.dll
O2 - BHO: McAfee Privacy Service - {cc4b2ee5-4803-11d7-8a38-00b0d0c6b814} - C:\Program Files\McAfee\McAfee Privacy Service\GDIEHELP.DLL
O3 - Toolbar: HP view - {B2847E28-5D7D-4DEB-8B67-05D28BCF79F5} - c:\program files\hp\digital imaging\bin\hpdtlk02.dll
O3 - Toolbar: McAfee VirusScan - {BA52B914-B692-46c4-B683-905236F6F655} - c:\progra~1\mcafee.com\vso\mcvsshl.dll
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\j2re1.4.2_03\bin\jusched.exe
O4 - HKLM\..\Run: [hpsysdrv] c:\windows\system\hpsysdrv.exe
O4 - HKLM\..\Run: [HP Component Manager] "C:\Program Files\HP\hpcoretech\hpcmpmgr.exe"
O4 - HKLM\..\Run: [HPHUPD05] c:\Program Files\HP\{45B6180B-DCAB-4093-8EE8-6164457517F0}\hphupd05.exe
O4 - HKLM\..\Run: [HPHmon05] C:\WINDOWS\System32\hphmon05.exe
O4 - HKLM\..\Run: [KBD] C:\HP\KBD\KBD.EXE
O4 - HKLM\..\Run: [Recguard] C:\WINDOWS\SMINST\RECGUARD.EXE
O4 - HKLM\..\Run: [AlcxMonitor] ALCXMNTR.EXE
O4 - HKLM\..\Run: [VTTimer] VTTimer.exe
O4 - HKLM\..\Run: [PS2] C:\WINDOWS\system32\ps2.exe
O4 - HKLM\..\Run: [AGRSMMSG] AGRSMMSG.exe
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [AlcWzrd] ALCWZRD.EXE
O4 - HKLM\..\Run: [Alcmtr] ALCMTR.EXE
O4 - HKLM\..\Run: [SpeedTouch USB Diagnostics] "C:\Program Files\Thomson\SpeedTouch USB\Dragdiag.exe" /icon
O4 - HKLM\..\Run: [MCAgentExe] c:\PROGRA~1\mcafee.com\agent\mcagent.exe
O4 - HKLM\..\Run: [MCUpdateExe] C:\PROGRA~1\mcafee.com\agent\McUpdate.exe
O4 - HKLM\..\Run: [MSKAGENTEXE] C:\progra~1\mcafee\spamki~1\mskagent.exe
O4 - HKLM\..\Run: [VSOCheckTask] "c:\PROGRA~1\mcafee.com\vso\mcmnhdlr.exe" /checktask
O4 - HKLM\..\Run: [McAfee Guardian] C:\Program Files\McAfee\McAfee Shared Components\Guardian\CMGrdian.exe /SU
O4 - HKLM\..\Run: [VirusScan Online] "c:\PROGRA~1\mcafee.com\vso\mcvsshld.exe"
O4 - HKLM\..\Run: [MSKDetectorExe] C:\PROGRA~1\McAfee\SPAMKI~1\MSKDetct.exe /startup
O4 - HKLM\..\Run: [MPFTray] C:\PROGRA~1\McAfee.com\PERSON~1\MpfTray.exe
O4 - HKLM\..\Run: [ATIPTA] C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [TkBellExe] "C:\Program Files\Common Files\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [Openwares LiveUpdate] C:\Program Files\LiveUpdate\LiveUpdate.exe
O4 - HKLM\..\Run: [Aqua Dock] C:\Program Files\Aqua Dock\Aqua Dock.exe
O4 - HKLM\..\Run: [iTunesHelper] C:\Program Files\iTunes\iTunesHelper.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [BackupNotify] c:\Program Files\HP\Digital Imaging\bin\backupnotify.exe
O4 - HKCU\..\Run: [Acme.PCHButton] C:\PROGRA~1\HPPAVI~1\Pavilion\XPHWWBS4\plugin\bin\pchbutton.exe
O4 - HKCU\..\Run: [Steam] "d:\program files\games\half-life 2\steam.exe" -silent
O4 - HKCU\..\Run: [Handy Backup 2.1] "C:\Program Files\Utilities\Handy Backup 2.1\nhbwp.exe" /s
O4 - Startup: OpenOffice.org 1.1.2.lnk = C:\Program Files\OpenOffice.org1.1.2\program\quickstart.exe
O4 - Global Startup: HP Digital Imaging Monitor.lnk = C:\Program Files\HP\Digital Imaging\bin\hpqtra08.exe
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\WINDOWS\System32\shdocvw.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\WINDOWS\System32\shdocvw.dll
O9 - Extra button: Privacy Bar - {cc4b2ee5-4803-11d7-8a38-00b0d0c6b814} - C:\Program Files\McAfee\McAfee Privacy Service\GDIEHELP.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: {26CBF141-7D0F-46E1-AA06-718958B6E4D2} - http://download.ebay.com/turbo_lister/UK/install.cab
O16 - DPF: {4ED9DDF0-7479-4BBE-9335-5A1EDB1D8A21} (McAfee.com Operating System Class) - http://download.mcafee.com/molbin/sh...3/mcinsctl.cab
O16 - DPF: {BCC0FF27-31D9-4614-A68E-C18E1ADA4389} (DwnldGroupMgr Class) - http://download.mcafee.com/molbin/sh...20/mcgdmgr.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{2B1F5B70-3C3B-4D16-8EDF-C005341F9FFB}: NameServer = 158.152.1.43 158.152.1.58
O17 - HKLM\System\CS1\Services\Tcpip\..\{2B1F5B70-3C3B-4D16-8EDF-C005341F9FFB}: NameServer = 158.152.1.43 158.152.1.58
O18 - Protocol: cetihpz - {CF184AD3-CDCB-4168-A3F7-8E447D129300} - C:\Program Files\HP\hpcoretech\comp\hpuiprot.dll
O23 - Service: Ati HotKey Poller - Unknown - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: ATI Smart - Unknown - C:\WINDOWS\system32\ati2sgag.exe
O23 - Service: Diskeeper - Executive Software International, Inc. - C:\Program Files\Utilities\DKService.exe
O23 - Service: McAfee Privacy Service - Network Associates, Inc. - C:\Program Files\McAfee\McAfee Privacy Service\GUARDDOG.EXE
O23 - Service: iPod Service - Apple Computer, Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: McAfee.com McShield - Unknown - c:\PROGRA~1\mcafee.com\vso\mcshield.exe
O23 - Service: McAfee SecurityCenter Update Manager - McAfee, Inc - C:\PROGRA~1\McAfee.com\Agent\mcupdmgr.exe
O23 - Service: McAfee.com VirusScan Online Realtime Engine - Networks Associates Technology, Inc - c:\PROGRA~1\mcafee.com\vso\mcvsrte.exe
O23 - Service: McAfee Personal Firewall Service - McAfee Corporation - C:\PROGRA~1\McAfee.com\PERSON~1\MPFSERVICE.exe
O23 - Service: McAfee SpamKiller Server - Networks Associates Technology. Inc. - C:\PROGRA~1\McAfee\SPAMKI~1\MSKSrvr.exe
O23 - Service: Pml Driver HPZ12 - HP - C:\WINDOWS\system32\HPZipm12.exe

Thanks!

Sorry, but this seems to have been overlooked. If you still need assistance, could you please post a new log?