>Is there any chance that this could be software ? If a bluescren occurred would there always be something in the event log ? If it is software, 95% of the time you will see something. Even if it is only a event saying recovering from bug check or preparing memory.dmp or dr. Watson. >This issue started at the same time we moved the hosting of this server to another company. The engineer there has assured me that the ups is up to the job. We also have another server on this ups which is not rebooting. This has nothing to do with the UPS. (Unless the UPS itself is starting to suffer some kind of failure.) What I mean by the power supply is the actual power supply inside the server. For example, we have a server that has 2 EIDE HD, 2 SCSI HD, 2 NIC cards, a total of 3 fans all running on a 300 watt power supply. All of a sudden, at around 11:00 PM and 4:00 AM the server would reboot. Nothing in the logs or memory dump. After a couple of days I saw a pattern. At 10:50 a batch file started that was doing a bunch of file updates. At 4:00 AM NAV was scheduled to do a complete virus scan. Both of these are disk intensive. So on a whim, I changed the power supply to a 480 watt and have not had a problem since. That's why I was asking about what hardware do you have. John Tolmachoff MCSE, CSSA IT Manager, Network Engineer RelianceSoft, Inc. Fullerton, CA 92835 www.reliancesoft.com