Motherboard shopping

[Doug]

Hello:

My computer takes two or three tries to get thought the boot sequence.
 It reboots at random times after it has booted.  I need to take care
of this issue, but I am not so good at diagnosing this sort of things,
so I am thinking of replacing the motherboard/chip/memory.  I did the
memory test for about a half hour, and nothing showed up.  The board
is a Sanyo bought as a MicroCenter discount item.

Given this experience, I would like a combination of board/chip/memory
that is rock solid reliable.  I guess that means ECC RAM.  I have been
buying AMD's of late, but if something from Intel is better over time,
I could go that way.  What would you buy?

doug