I downloaded some updates for my XP a couple of weeks ago and they messed my comp but not as bad as yours sounds. To cure it I had to restore back to just before the updates and it's been fine ever since.
Any chance you could restore back to, in your case, a couple of months??
They are stopping updates next year anyway so I don't think loosing a few updates will matter. You would think that they could have had it working first class by now without all these extra updates, wouldn't you?