Thanks, Ace.
I've actually upgraded my Ram since the building of the system and still
suffer the same dilemma. I am wondering if it might be a motherboard issue.
All hardware has current drivers and is new for this system (except for HDs).
I have run the memory test which Vista offers and have found no problems.
My older system also uses a great deal of CPU when video editing, but it
doesn't suffer the random reboots. This is why I think (hope) it might be a
MB issue. We'll see.
Thanks again,
Miles

BTW, thanks for the tip about core selecting. I wasn't aware I could do that!