This security vulnebility patch was available a month before this worm like Virus.
There are "mutations", or variation of the MSBLAST.EXE worm. LOVESAN and TEEKID or something like that, they're the variations of it.
It predominently overloads the stack so Win XP shuts the system down and W2K just seems to cause the SVHOST or something like that to crash.
Basically if ppl had kept their pcs up to date with security patches none of this would have happend.
Not patching a pc is like not servicing your car, eventually its bound to shit itself one way or the other, directly or indirectly.