System shutting down during logon

Done, Thanks again

OK, Event Viewer, yes there certinally many entries there. Some are errors and some are warnings. Looks like many are at startup and associated with Microsoft Security Essentials which I just loaded a week or so ago. Looks like trouble updating at startup and Stoped error 0xc000000D. There are many other errors that have been going on for some time. Where do I start?

No Blue Screen and nothing under Windows Error Reporting in System Information.

I ran the MEMTEST86 yesterday and NO ERRORS. It ran for 15 hours and made almost 8 passes. I guess Mem is OK. I did have IE9 loaded on this machine and then removed it. I put it back on late yesterday and durning startup only had two errors in Administrative events, both having to do with updates.
Error 1
Session "Microsoft Security Essentials OOBE" stopped due to the following error: 0xC000000D

Error 2
Failed extract of third-party root list from auto update cab at: <http://www.download.windowsupdate.com/msdownload/update/v3/static/trustedr/en/authrootstl.cab> with error: A required certificate is not within its validity period when verifying against the current system clock or the timestamp in the signed file.

Any ideas??

No Yellow warnings on devices. All look OK. I sent e-mail to windows support for assistance because having to do with updates and MSE. This is my only anti Virus and want to make sure updated regualy.

If you think it might be Microsoft security essentials, one option would be to download a fresh copy, uninstall it, and reinstall it. Might want to reboot between the uninstall and reinstall. Let it update and then do a full scan. If memory servers me, there was a virus floating around that would cause your PC to reboot. Aside from being a pain in the but it was relatively harmless compared to some other nasties on the web. I'm not saying that is what is causing your problems but doing a good scan with MSE probably wouldn't hurt just to rule out an infection of some type.