I have a "Windows Explorer has encountered a problem & needs to close" issue that is similar to that covered in the Post by "pvo01 10/10/2008 Windows Explorer Crashed" on my PC. This PC system was newly built & purchased in August this year with XP Home Version 2002 Service Pack 2. It is lightly used mainly for Internet email (Yahoo) & browsing, plus minimal Word/Excel (2007) use. It connects to the same Router used for my Notebook Internet connection. It also has the Hard Disk from a 'prior' system installed as Drive F (ie additional to the main Drive C) - for access to historical data only. I installed AVG 8.0 three weeks ago (run daily), and the Windows XP Firewall is switched on. Don't think any OS updates have been run either. The main characteristics of this problem are: - Boots ok, then immediately (without any mouse/keyboard activity) displays the Win Explorer message (AppName: Explorer.exe, ModName: msi.dll). - Providing I do not click the Send/Don't Send buttons on the message box, the desktop functions normally except: i) Start Menu/All Programs freezes the system, ii) as does using the 'New' option on the context-menu (anywhere it appears), iii) trying to start Word or Excel (2007) gives an "Explorer.exe Application error" with the notation "Memory ..... could not be read", iv) the Control Panel/Add or Remove Programs option gives a "Run DLL as an App. has encountered...." message (AppName:Rundll32.exe, ModName:msi.dll). If I do click the Send/Don't Send buttons, the desktop refreshes, (incl. the Win Explorer message) then freezes, with the Task Bar showing only the Start button, and the Time. The cursor changes to the hour-glass anytime it is placed over the taskbar. I've followed the 8-Step plan - very helpful thankyou - except for the following: Step 2. - Only Win XP Firewall in use Step 5. - SuperAntiSpyware not able to be installed. Gives a "MSIEXEC.exe has encountered a problem ...." message (AppName:msiexec.exe, ModName:msi.dll). Step 6. - Java not installed on this system. Nothing was picked up by AVG or Malwarebytes, (nor Hijackthis as best I could see). Note that I have subsequently uninstalled AVG, as the 'Scan file' option in the context-menu was not running a file or folder scan as it should. I had also noticed that spurious (ie non-scheduled) 'AVG Updates' were being run, followed by a "AVG Update requires a Restart" message - which made me somewhat more suspicious about AVG. The only 'non-standard' entry on the context-menu is now the 'Scan Malwarebytes'. I would very much appreciate your help & advice on where to go from here. I'm wondering if there may be a corruption in the OS somewhere. I haven't run a Windows Repair as yet - still looking for the CD's! Is faulty RAM also a possiblity? I have not attached the log files as yet, as I figured you would prefer to see these run as a complete set after the SuperAntiSpyware problem is fixed (hopefully). Thankyou in advance.