Hi
thank you for heads up.
I prefer to manually check MSE updates.
Never faced a BSOD.

@ copmom do you have other antivirus installed or other incompatible software?

How to manually update MSE

http://www.microsoft.com/security/portal/Definitions/ADL.aspx

Fix MSE Utility - Repair Microsoft Security Essential

However, just in case anytime, you find that you are facing any issues in running Microsoft Security Essentials due to any reasons, simply run this utility. This utility will restore all its registry values & service settings to known good defaults, without re-installing MSE. The utility may take only a moment to run, but rest assured, it does the job! It works on both 32bit and 64bit of Windows Operating Systems.

And.. I might add, they never sent out a 'fix' on that last Security Update KB971486 ..
because of that it still takes me 8 full minutes on start up to get past that BSOD (blue screen of death), before my start button, task bar, and icons show up! I've tried everything and a lot of things that Robert so kindly suggested, to no avail!

http://www.h-online.com/security/news/item/Microsoft-anti-virus-software-dawdles-over-updates-838203.html

No, 10 day-old signatures are NOT up to date and do NOT offer adequate protection. Vergrößern Under certain circumstances, Microsoft's recently launched Security Essentials (MSE) security solution fails to download updates for several days