Were there any recent updates or changes or patches were applied? what do you see in armonitor.log?
I came across these two discussions, that may give you heads up.
Here is KA to how turn on the start up logging:
I do not see any information to troubleshoot in arerror.log file and armonitor.log file.
I tried to restart the server with checkdb option and everything from DB end looks good. Might be some MS security patch issue.
I am still investigate the cause..... Will let you know if I find anything useful.
Thanks for posting those links....