It seems Microsoft has known about an extremely severe security flaw in Windows XP and has delayed fixing it until SP 1.
This bug is so trivial to exploit that those of you with Windows XP Home or Pro need to fix it immediately. It is quite literally possible that visiting a webpage or clicking a certain style of URL (link) can overwrite any file on the hard drive. That means just by viewing a webpage your system would be dead.
For those of you who can't stand to put up with Microsoft's insane new EULA agreement and provisions for SP 1, there is a patch for this major flaw on grc.com.
You need to fix this immediately. This flaw is so bad and so trivial to exploit that just by typing a certain string of characters I could have ruined all the Windows XP machines who viewed this post.

It absolutely amazes me just how bad M$ products have gotten recently. This should have been patched immediately when found, not 3 months later.