One day, without having made any changes on my computer (running Windows 2000 Professional, SP3, IE6 SP1) it suddenly began misbehaving.  I kept getting error messages -- pop-up windows with a red "X" saying explorer.exe referenced memory location 0x00000000, which could not be "read".  Whenever I clicked "OK" the desktop icons disappeared (and any open instances of Windows Explorer or Internet Explorer closed), and another identical box promptly appeared.  It didn't take too long (how many times will you stomp on your own foot before you realize its better not to do that) for me to get the idea of moving that error box to the side of the screen, which allowed me to use the computer normally as long as I never closed it.

I called the guru at work, and he gave me some good suggestions: uninstall any recently installed programs, as well as anything you don't intend to use ever again; start up in "safe mode", and then reboot in normal mode (that error message popped up in safe mode, too).  Do a virus scan.  Clear your Internet Explorer cache, delete cookies, etc.  Delete Temp files, empty the trash.  These are all good suggestions, but none of them worked.  So I did a Google search (search arguments: explorer.exe referenced memory could not be read), and came up with a page that gave the following info:

The Problem

(This is the problem described on the web page, which was similar to my problem.)

Every time I boot and log into Windows 2000, the desktop begins to appear and then one of the following windows appears:

--and/or--

If I click OK on the first window, explorer closes, the desktop disappears, re-appears and then the error appears again. (Note - the memory address is not always the same)

If the second window appears, explorer closes by itself automatically and then the desktop disappears, re-appears and then the error appears again.

The errors also occur in Safe Mode.

I can End Task on explorer.exe before the error occurs and run almost any program (except explorer.exe) through the Task Manager File\Run command - (finding the correct commands and switches has been fun!)

I have done a complete online scan for Viruses at Symantec's site... It is Safe and Clean

I have installed and uninstalled Win2K SP4 and IE 6 with all updates.

I have run the repair options with the Win2K Pro CD.

I used Dell's diagnostic tools to verify the memory and hardware

Solutions:

These came from website   http://www-level3.experts-exchange.com/

Repair IE

Start > Run rundll32 setupwbv.dll,IE6Maintenance "C:\Program Files\Internet Explorer\Setup\SETUP.EXE" /g

or

Start > Run rundll32.exe setupapi,InstallHinfSection DefaultInstall 132 C:\windows\inf\ie.inf

Reinstall IE

Description of the Internet Explorer Repair Tool
http://support.microsoft.com/default.aspx?scid=http://support.microsoft.com:80/support/kb/articles/Q194/1/77.asp&NoWebContent=1

How to Reinstall or Repair Internet Explorer and Outlook Express in Windows XP
http://support.microsoft.com/?kbid=318378

Repair Internet Explorer 6
http://www.theeldergeek.com/repair_ie6.htm
http://support.microsoft.com/?kbid=293907

Unable to Open Link
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q281679&sd=tech

IE Eradicators

http://www.litepc.com/ieradicator.html

Obsolete link: www. webattack.com/get/ieradicator.shtml

Downloads

IE Download (From 2.0 to 6.0) and Service Packs/Patches
Obsolete link: helpdesk.uvic.ca/how-to/support/win95/msiexpl.html

IE Download (From 1.0 to 6.0) and service Packs
http://browsers.evolt.org/?ie/32bit

Also check for spywares

Spyware/Adware removal tools

What is spyware: http://www.spychecker.com/spyware.html

SpyBot-S&D: http://www.snapfiles.com/get/spybot.html 

Ad-aware: http://www.snapfiles.com/get/adaware.html  

Trojan Remover: http://www.simplysup.com/

HijackThis: Obsolete link: www. webattack.com/download/dlhijackthis.shtml

KL-Detector: http://www.snapfiles.com/get/kldetector.html  

X-Cleaner Free: http://www.snapfiles.com/get/xcleaner.html 

SpywareBlaster: http://www.snapfiles.com/get/spywareblaster.html 

SpywareGuard: Obsolete link:  www. webattack.com/download/dlspywareguard.shtml

SpySites: Obsolete link:  www. webattack.com/download/dlspysites.shtml

Keylogger Hunter: Obsolete link: www. webattack.com/download/dlklhunter.shtml

Spycop: http://www.spycop.com/

Goodbye Spy: http://www.topshareware.com/GoodBye-Spy-download-2012.htm