Windows Explorer fails to open

[Clamorous]

I'm using a Dell OptiPlex 745, Windows XP Professional, SP2 with all
updates (probably except the last since this is a corporate machine
and IT takes care of the updates).

I usually have two Windows Explorer windows ope all the time. I run
into a problem that seems to be getting more frequent where, when
trying to open another window (right click start and select Explore) I
get a message that it encountered a problem and needs to close, ya-da,
ya-da, ya-da. From this point on I can't open another Explorere
window. Sometimes I can start "My Computer". If it does start, when I
go to close it I'll get the same error. Or, sometimes I get the error
message when trying to open (double clicking My Computer on the
Desktop). In either case from this point on I can't open either. When
I double click on My Computer the hourglass flashes quickly, then
nothing. Not even an error message. Another strange point is that when
I get the first error message and exit that window, the two open
Window Explorer windows stay, other times they go away too.

Last week I had this problem immediately after booting on Monday
morning. This week the problem didn't show up until Wednesday
afternoon. Last week I rebooted the PC and didn't have a problem for
the remainder of the week.

IT has scanned the PC and didn't find anything.

Any ideas?
Thank you.

 

[Elmo]

I'm using a Dell OptiPlex 745, Windows XP Professional, SP2 with all
updates (probably except the last since this is a corporate machine
and IT takes care of the updates).

I usually have two Windows Explorer windows ope all the time. I run
into a problem that seems to be getting more frequent where, when
trying to open another window (right click start and select Explore) I
get a message that it encountered a problem and needs to close, ya-da,
ya-da, ya-da. From this point on I can't open another Explorer
window. Sometimes I can start "My Computer". If it does start, when I
go to close it I'll get the same error. Or, sometimes I get the error
message when trying to open (double clicking My Computer on the
Desktop). In either case from this point on I can't open either. When
I double click on My Computer the hourglass flashes quickly, then
nothing. Not even an error message. Another strange point is that when
I get the first error message and exit that window, the two open
Window Explorer windows stay, other times they go away too.

Last week I had this problem immediately after booting on Monday
morning. This week the problem didn't show up until Wednesday
afternoon. Last week I rebooted the PC and didn't have a problem for
the remainder of the week.

IT has scanned the PC and didn't find anything.

Any ideas?
Thank you.

Click Start, Run, type SFC /SCANNOW, click OK. If any files are damaged
or missing, they'll be replaced. You may need to reboot afterwards so
damaged files will be replaced.

 

[Ron Badour]

I would suspect malware or another program running in the background is
causing the problem. Malware can be detected by any number of good programs
(SpyBot for one) and the other is detected using this method:

How to perform advanced clean-boot troubleshooting in Windows XP
http://support.microsoft.com/?kbid=316434

Spybot: http://www.safer-networking.org/en/download/

Since the problem is not consistent, it might be a real bear to track down.