Question 1 RAM fails after Microsoft Security Essentials update

[Nard333]

I have 2 different 4gb ram KVR13N9S8/4(1333mhz) and KVR16N11S8/4(1600mhz). They are working perfectly for 5 days until today. A few minutes after the system starts, the blue screen of death showed up and automatically restarts the pc, after the restart my system can now only detect single stick of 4gb the KVR13N9S8/4(1333mhz). The last system update that was made is the Microsoft Security Essentials update roughly the same time the blue screen occur. Is that possible? An update can cause the ram to be faulty or the ram is just plain faulty and this is just a coincidence? What could be the reason?

If the Microsoft Security Essentials update is the reason then I'm thinking a System Restore, is that advisable?

 

[PC Tailor]

Sooner sounds like the RAM could just be faulty, the update could have simply helped expose the issue.
Does the issue still occur in safe mode?
Have you ran memtest to check for RAM module faults?

What BSOD error do you receive, do you have a dump file?