Frequent Blue Screen Crashes (PLEASE HELP)

My computer keeps experiencing what I think are called 'blue screen' crashes.
The screen does not turn blue; rather it freezes and the graphics become
heavily pixelated and distorted. I think it also turns progressively black
over an extended period of time.

It's an old Dell laptop running Windows XP Home Edition and when the problem
started I used to get a link (on restarting) to this site:
http://wer.microsoft.com/responses/R...e5719c196#here

I do not get this link any more but I have no reason to doubt it is still
the same problem. I have tried the advice offered here but to no avail.

I have also spoken to Dell and been taken through the diagnostic tests for
my computer, which failed to find any problems. According to Dell this means
there is nothing wrong with the video card; rather Windows needs
re-installing. I have also spoken to the video card manufacturer who say
that, based on the symptoms, there is a problem with the video card and it's
nothing to do with Windows.

Any suggestions for resolving the problem would be much appreciated. I
should also say that I used to connect the computer to a TV from time to time
to watch movies (involving changing some of the display settings) which may
have started the problem but I don't do that any more.
--
Karim434