I downloaded Portal on Steam a few weeks ago as it was free, and I wanted to see what it was all about, but when I tried to play it, it kept saying that my graphics card driver needed updating.
Went to the cards website and downloaded the latest driver software, and got a warning when I tried to install it, saying it wasnt verified with Windows XP yet, so may not function correctly.

After deciding to not take the risk, I mulled it over a few days later, and decided to take the risk.

Everything seemed fine at first, and portal worked fine.

After a few days, I started to have problems with videos online, with them not running as smoothly as before or freezing.

So I decided to go back to the old driver.

Everything seemed ok, but then I noticed that somehow it had reactivated or reinstalled the new driver again.

Removed everything, and started from scratch, and once again things seemed fine.

Next thing that happened is that I got a pop up saying that a new version of Adobe Flash Player was available and needed installing, so as per normal, I did the upgrade like I do with pretty much any software when it goes out of date.

First thing I noticed with the new Flashplayer was that I was getting some kind of corruption on embedded videos when they were posted here or on Facebook etc. (the writing on the static screen shot before you press play was always a blue corrupted graphic text)

After a while I started having issues with videos freezing up and even kept having warnings that flash player had crashed.

Tried reinstalling flash player several times, but still had the same problems (it was happening in both Firefox and Chrome).
Next thing to do was totally unistall it and do a fresh install.

After reinstalling, everything was running fine in Chrome and Firefox, so all seemed good (although the blue text corruption was, and still is, present).

Then yesterday I turned my screen saver back on as it hadnt been turned on for a few months, and I kept getting a black screen with a text message saying that I needed to install certain flash plugins.
Looked at Adobe site, but couldnt find anything specific to it, so I gave up.

Today, I went to play and FLV file I just downloaded, and it said that I needed to download flash player for IE.
Opened IE, and went to the Adobe site to download it, and every time I tried, IE kept freezing up.

In the end I opened up Chrome and google searched active x for IE, and downloaded the IE flash player from a different site.
Installed it, and now the flv files play and my screen saver works again.

Its just pissing annoying that these progs dont work properly half the time, and you end up running round in circles trying everything until things work again.

So it now means I am on the latest driver for my graphics card, and have the latest flash player, and they work, no thanks to the original vendors.