Edit: Ken has pointed out that WGA doesn't get installed automatically - I must have installed it by visiting Microsoft Update. Still doesn't change the problem, though.

The other day I was playing around on my PC and noticed that it was downloading an update. When it had finished, I checked my "Add or Remove Programs" dialog to see what it was. Turns out it was the latest version of the Windows Genuine Advantage Validation Tool.

For those who don't know what the WGA program is: it's a method used by MS to ensure that you're not running a pirated version of Windows. I think they keep a registry somewhere of license keys that they know haven't been "compromised", and you can (voluntarily) check your Windows against that registry using this tool.

Now, although the program is voluntary, there are certain key benefits to using it. The main thing to keep in mind is that it's mandatory if you want to use Windows Update (now known as Microsoft Update). Attempting to do a scan for updates will always activate the WGA tool.

Now, my Windows is definitely genuine. I visit Microsoft Update all the time, and I'm running software that I've downloaded from MS which I couldn't have installed had I not been running a genuine copy of Windows (stuff like Windows Defender and IE7).

Imagine my surprise, then, when Microsoft Update froze my computer!

Ever since the latest WGA tool was installed (as part of visiting the Microsoft Update site and attempting to perform a scan) I have been unable to get to any page on Microsoft's web site that requires validation. Attempting to do so freezes every process on my PC, forcing me to power down (Ctrl+Alt+Del doesn't work either).

So I had a poke around the MS newsgroups, and found this thread. Turns out I'm not the only one!

Right now the going theory is that it's something to do with hardware. Those of us who have posted our PC specs to the thread are all running an Athlon64 CPU with an nForce motherboard.

Until this issue is resolved, I can't get to Microsoft Update, which sucks a fair bit. Other than that everything runs just fine ... so at least it's not preventing me from working on Comicster or (worse still) playing Minesweeper.