[NTLUG:Discuss] somewhat odd boot behavior

[Fred James]

Gigbyte(tm) S-Series G41M-ES2L motherboard
Intel Dual-Core E6600 LGA775 cpu
ATX-1072BP case from Frys (380W power supply)
OS: Mandriva 2008.0

Has been running since December 2010 ... but boot/reboot has always been 
a bit odd

On every other Intel based Linux box I have seen ...
    System -> Shutdown -> Restart preforms an orderly warm reboot
    System -> Shutdown -> Shutdown preforms an orderly power down
On this machine, both Restart and Shutdown preform a restart of X, at 
which point one may either press the restart or the power button, on the 
front of the computer.

I have been over the motherboard manual, bios setting, and google, but I 
cannot find anything that strikes the eye (except all the stuff designed 
for Win7 ... but not explained)

The only machines I have seen this on before were SGI Origin 200s 
running IRIX ... I have seen SGI's name pop up on startup, and certain 
other features of the startup screens look familiar as well

Any thoughts, comments, experience, pointers?  Other list to ask?  Thank you
Regards
Fred James