I can say that all the DOS code should be long gone, since XP marked the move to the NT platform, which was based on OS/2 if anything. DOS effectively died with WinMe. This is why a lot of programs stopped working so well when XP came along. That, and it started actually enforcing certain programming habits that people SHOULD have been using since Win95 anyway.
But let's put it rather simply. This is a HELP oriented forum, so people have a tendency to naturally assume you're here looking for... wait for it... HELP.
To that end, if you're getting a blue screen error, that means you either have some sort of hardware failure, or just a buggy driver. Loads of people will go out, buy the cheapest pile of crap computer they can find, then attach equally steaming piles of crap accessories like printers, and they then seem genuinely mystified when the end result is just an even bigger steaming pile of crap. It's like they expect some kind of magical alchemical transmogrification to take place so that you put garbage in, and get pure gold coming out. In the land we call reality, this sort of thing doesn't happen. You put garbage in, you get garbage back. Sometimes the level of garbage increases, so what you end up with is actually worse than the sum of the two parts individually, but never does it work the other way around. So if you're getting a blue screen, it's because you're introducing garbage into the equation somewhere.
Now, if you want to say that Windows could handle these situations a bit more gracefully, maybe offer up an error message that's understandable to most people for example... Well, that would be a fair point to make. It is important that you recognize what is and isn't Microsoft's fault so that the blame can be appropriately distributed. Blaming Microsoft for something that's A) not their fault, and B) beyond their control is hardly what you'd call productive.
The last time I ever saw a BSOD on any of my systems was my old Compaq P-150 running Win95. I also had a few with my Packard Bell 486 running Win 3.11 before that. Of course both of those fall into the garbage in category outlined above. Maybe before you're so quick to blame others, you should look at what "joys" you've visited upon yourself.