I'm out of ideas here. We have a 2008 Server that keeps rebooting 2-3 times a day at completely random times with an "Unexpected Shutdown" event. There are no Dumps, no events leading to it just like it loses power then comes back online. I ran a Diagnostic of the power supply and it has had continuous power for months. In addition, the temperature of the processors are maxing out at 40 degrees Celsius. Anyone have any ideas how to figure out why this is restarting all the time? This is a DMZed Web server so it doesn't do too much process wise. Here are the specs:

Host Name:                 ~~~
OS Name:                   Microsoft Windows Server 2008 R2 Standard 
OS Version:                6.1.7600 N/A Build 7600
OS Manufacturer:           Microsoft Corporation
OS Configuration:          Standalone Server
OS Build Type:             Multiprocessor Free
Registered Owner:          Windows User
Registered Organization:   
Product ID:                ~~~
Original Install Date:     5/27/2010, 4:25:47 PM
System Boot Time:          2/14/2011, 5:35:01 PM
System Manufacturer:       HP
System Model:              ProLiant DL380 G6
System Type:               x64-based PC
Processor(s):              1 Processor(s) Installed.
                           [01]: Intel64 Family 6 Model 26 Stepping 5 GenuineIntel ~1586 Mhz
BIOS Version:              HP P62, 8/16/2010
Windows Directory:         C:\Windows
System Directory:          C:\Windows\system32
Boot Device:               \Device\HarddiskVolume1
System Locale:             en-us;English (United States)
Input Locale:              en-us;English (United States)
Time Zone:                 (UTC-05:00) Eastern Time (US & Canada)
Total Physical Memory:     4,086 MB
Available Physical Memory: 2,775 MB
Virtual Memory: Max Size:  8,170 MB
Virtual Memory: Available: 6,691 MB
Virtual Memory: In Use:    1,479 MB
Page File Location(s):     C:\pagefile.sys