Some times simple things get over looked, these are just my observations whether they are true or not I don't know but it makes me feel better! I think some of this code is unstable so I defrag at least once a week now, I also couldn't log in after a patch and I did react badly as well, then I remembered that sometimes patches and up-dates need to be re-booted so I did and got straight in next attempt! It was just that simple or maybe slap your anti-virus proggie a bit?
Hope to see you soon!
G'luck