Today, I read two [1] [2] interesting and alarming articles from Ed Bott where he describes several cases of Vista users having serious problems with Windows validation.

They activated their Windows Vista correctly, but after installing software, their system went into a non-genuine state. Some of them were not even able to activate it again. If you feed Google with the corresponding error code 0xc004d401, you already get a considerable amount of hits. One of the programs that caused this problem is Trend Micro Internet Security. So, these guys didn’t just install some hacker tools. Microsoft meanwhile confirmed this problem in a KB article, admitting that it is a Vista bug.

It seems that only retail customers were affected by this problem, so far. But imagine that after deploying the latest antivirus software in your network, all your Vista machines go into a non-genuine state and can’t be activated again.

In my view, these incidents show how dangerous WGA is now. Perhaps, the real threat doesn’t come from regular software, though. I’m sure that some bad guys are already pondering on ways of how to exploit this new Windows’ weakness. Let’s just wait for the next computer worm capable of deactivating Vista.