Thanks for the very comprehensive reply Andre.

I have been using Avast since new (about a year), Microsoft Defender and
Windows Firewall through a Netgear router. Both Avast and Defender scans
show clean. I don't normally visit sites that I don't know to be safe, and
never open unknown attachments. Generally, I doubt that I have any malicious
software running (though I am *not* overly knowledgeable in this area).

My machine is a laptop, and afaik, has the original OEM drivers installed.
Also, I didn't mention in original post ,though I meant to - I only have the
original installation accounts i.e. Administrator, Me and guest (guest is
disabled) - I normally run in the Me account and it is in this account that
Explorer faults - when I have run the Administrator account, I haven't seen
the same fault(s). The Me account is the default as initial setup and is an
administrator account even though it doesn't seem to actually have the
permissions that the main Administrator account has.

I should also mention another problem that *may* be relevant - from my Me
account, if I try to delete (for example) the remnants of an uninstalled
program folder from Program Files - it goes through the motions prompting to
continue then showing the progress bar - but in fact doesn't actually do the
deletion - the folder/files remain intact even though it seems to have shown
the deletion completing normally. This, I * think* started happening at the
same time as the explorer problem. Another example of the same would be
deleting a shortcut from the start list - it appears to complete but doesn't
actually do the deletion. I need to go into the Administer account to get
the deletions done. (even though the Me account is an administer account
too)

I have tried various aspects of your post, but some are beyond my ability.
The only thing that has attracted my attention is the following from the
event viewer:

1284 of the these events:
----------------------------------
Faulting application Explorer.EXE, version 6.0.6000.16549, time stamp
0x46d230c5, faulting module ntdll.dll, version 6.0.6000.16386, time stamp
0x4549bdc9, exception code 0xc0000005, fault offset 0x00042e7b, process id
0x38c, application start time 0x01c83db6a30ae5f8.
----------------------------------
and a whole bunch of these events:
----------------------------------
The description for Event ID 1000 from source Application Error cannot be
found. Either the component that raises this event is not installed on your
local computer or the installation is corrupted. You can install or repair
the component on the local computer.

If the event originated on another computer, the display information had to
be saved with the event.

The following information was included with the event:

Explorer.EXE
6.0.6000.16549
46d230c5
ntdll.dll
6.0.6000.16386
4549bdc9
c0000005
00042e7b

The substitution string for insert index (%1) could not be found
----------------------------------

Thanks again for your helpful reply.

"Andre Da Costa[ActiveWin]" <andred25@hotmail.com> wrote in message
news:%23xI5tUPQIHA.1208@TK2MSFTNGP05.phx.gbl...
> Rick Rogers [MVP] on possible causes for Explorer
> crashes:
> Explorer doesn't just crash without reason, it does so because something
> is
> interfering with the process. It could be antivirus software, it could be
> malware (you may not be as clean as you think), or some other process. You
> might also check installed plugins for IE, as IE and Explorer share
> several
> modules and bad addons can interfere with explorer. Disabling them from
> loading may help.
>
> Additional information by Malke that could be useful:
> 1. First try updating your drivers. See below for general drivers
> information.
>
> 2. If the drivers are already correct, then do a clean-boot to make sure
> the problem isn't being caused by something running in the background.
>
> How to perform a clean boot in Vista and XP -
> http://support.microsoft.com/kb/331796
>
> 3. Look in Event Viewer for clues. MS TechNet link on how to run Event
> Viewer - http://tinyurl.com/2jejzc
>
> 4. If none of the above helps, do hardware troubleshooting.
>
> http://www.elephantboycomputers.com/...ardware_Tshoot
>
> *****
> Drivers - The First Law of Driver Updates is "if it ain't broke, don't
> fix it". Normally if everything is working you want to leave things as
> they are. The exception is that heavy-duty gamers will usually want to
> update their video and sound drivers to squeeze every last bit of
> performance out of the hardware to get the fastest frame rates. If
> you're not one of those people, you don't need to update your drivers if
> there are no problems you are trying to solve.
>
> Never get drivers from Windows Update. Get them from:
>
> 1. The device mftr.'s website; OR
> 2. The motherboard mftr.'s website if hardware is onboard; OR
> 3. The OEM's website for your specific machine if you have an OEM
> computer (HP, Dell, Sony, etc.).
>
> Read the installation instructions on the website where you get the
> drivers.
>
> To find out what hardware is in your computer:
>
> 1. Read any documentation you got when you bought the computer.
> 2. If the computer is OEM, go to the OEM's website for your specific
> model machine and look at the specs (you'll be there to get the drivers
> anyway)
> 3. Download, install and run a free system inventory program like Belarc
> Advisor or System Information for Windows.
>
> http://www.belarc.com/free_download.html - Belarc Advisor
> http://www.gtopala.com/ - System Information for Windows
>
> If you have installed drivers from Windows Update, you can roll them back:
>
> Roll Back Troublesome Device Drivers in Windows Vista from the How-To
> Geek - http://tinyurl.com/346lox
>
> --
> Andre
> Blog: http://adacosta.spaces.live.com
> My Vista Quickstart Guide:
> http://adacosta.spaces.live.com/blog...3DB!9709.entry
> "Les" <completelyfalse@mailaddress.toavoid.spam> wrote in message
> news:OG%23JtRPQIHA.4476@TK2MSFTNGP06.phx.gbl...
>> Hi
>>
>> Vista Ultimate - fully up to date
>>
>> Just recently, after using for several months, I am getting a pop up
>> dialog telling me Windows Explorer has stopped and do I want to restart
>> it. I always choose restart and it will happily restart until the next
>> time - which could be anything from 2 min to an hour. Also, it seems to
>> be invoked quite often when I try to open a folder to view contents, but
>> is not consistent in that I may open a folder several times and then
>> Windows Explorer will stop on the next attempt.
>>
>> I can't pin down any particular function that will cause this, it has
>> happened at all sorts of times, once even on restarting Vista after a
>> Vista Update required it - sometimes Windows Explorer will just stop when
>> I am reading email / surfing / playing solitaire etc - doesn't seem tied
>> to any particular operation.
>>
>> Anyone hint at a fix? Or, perhaps, what/how to repair with an OEM
>> installation CD?
>>
>> --
>> regards,
>> Les Hay, Livingston, Scotland
>
>



--
regards,
Les Hay, Livingston, Scotland