Unexplained system freezes

[neil]

For a while now my computer has been experiencing system freezes where the
entire computer just ceases to function. The last

thing I was doing continous to display and all input from mouse and keyboard
are met with no response, this includes

CTRL+ALT+DEL. Another piece of the puzzle is, this problem occurs at random
during most of my programs, except for the

following 2 programs where it crashes very shortly after use:
#1. Microsoft Word 2003 - Doing nothing special, I can simply be writing
plain black text and suddenly the system freezes.
#2. A shockwave/flash game on the website www.neopets.com , accessed by
Internet Explorer 7.

The system is not overheating according to both "SpeedFan" (utility) and
physically touching the HDD and CPU Heatsink (being

grounded both times hehe). I looked in Windows EventViewer and found no
errors nor warnings that could explain this freezing.

I ran the utility "HijackThis" and found nothing suspicious. A fully updated
virus scan using "AVG" revealed no viruses.

Finally Windows Firewall runs all the time.

So far I have tried the following (in order) and each of these changes did
not stop the problem:
# A new PSU
# Two new RAM sticks (replacing the existing)
# Updated drivers for existing AGP gfx
# Used built-in GFX and updated the drivers accordingly
# A brand new AGP GFX card with updated drivers
# Updated drivers for network card
# A new HDD with fresh copy of WindowsXP (including SP2 and all updates)

Frankly I am at a lost as to the cause.
Your thoughts please?
Neil.

 

[Guest]

This is one posibility, since both those apps use COM+

FIX: You may experience a system freeze when you try to cancel a COM+ method
by using the CoCancelCall method while a COM+ object that uses the
CoCreateInstanceEx method is instantiated in Windows XP Professional :
http://support.microsoft.com/kb/889178/en-us