On the above date we had very slow logon problems with several random computers at work.
recently installed the Microsoft Endpoint Security software - this worked fine for several weeks.
Some Windows 7 (32 bit) pc's previously fine, took up to 20 minutes to log in.
Some hanging at applying computer settings, and some applying user settings.
Jury is still out on this one, anybody had similar problems around that date, and if so did you find the root of the problem.
I am suspecting a rogue update

We have done some o/s rebuilds and are unable to simulate the fault again on the new builds.
some of the original affected pc's have been acting ok/slow intermittently.
other windows 7 computers on the network have been unaffected.
Strange.