I'm sure it's a bug, but I've managed to crash XP to the point of restarting at least a dozen times in the last few months, when I program various projects. I would be very surprised if a computer that decided to allow randomly mutating naked apps didn't need to be restarted, or even reformatted, quite often. Computers are carefully oiled machines that do not like things bumping where they should have bopped, so to speak.
I can't disagree. XP has may serious architectural problems (not fixed in Vista) not the least of which is that it deviated significantly (against Dave Cutler's objections and for reasons like RAM prices which are no longer relavant!) from it's NT micro kernal ancestory in that a whole bunch of stuff that should run in user mode actually runs in kernal mode (like User and GDI). This means there are millions of lines of code running in ring 0 that can take out the OS. Lots of surface area for OS bugs.
Even ignoring bugs, user mode apps can still muck things up by doing such things as allocating excesive kernal mode resources (which require the allocation of non-swappable kernal mode memory) like semaphores or file handles. While the kernal won't crash, a user mode app that does these kinds of things can cause the machine to become unusable for the human, requiring the OS be restarted.
Most problems though are with drivers or other thrid party kernal mode code like AV file filters that are either buggy or introduce API incompatabilites so that other programs have problems. Then there are the compatability switches... XP recognises hundreds of specific programs and actually changes the behaviour of system APIs to preserve behaviour they expected from previous versions in an effort to run as many things as possible even if they are technically incorrect.... Soemtimes these do the wrong thigns for the wrong programs.... In short, its a mess.
That said, there are many many millions of computers in the internet. I used to be heavily invovled with anti-virus stuff. Just like biological viruses, software viruses and worms that get released to the wild can take many years to go away completely, if ever. There are always unpatched machines, machines not running AV, machines for the which the user jsut lives with tehe problem, back-up tapes, infected machines that get turned on again after years, etc. The population gets knocked down when a patch or an AV signature comes out for them, but they are all still out there running somewhere, for many years. My point is that while yes, the vast majority of self-propagating, self-mutating viral organisms would crash, or get caught, or destroy their environement, or piss off the user, etc. , this just means that selection would favor the ones that were well behaved. Eventually, symbioisis could develop. Of course, were someone really interzxsted in doign this, the design of the bootstrap first organism would be critical.