First, try swapping some of the ram that's just under the daughter board, there's 6 or so socketed ram all in a row. Take the first one and the second and swap them, then the second and third, etc. and each time power back on. If the problem changes, then one of those ram is screwed up.
The other 4 they're talking about may be the problems too but they're likely soldered in, so it's easier to check the other ram first.
NOT AN EXPERT, just giving you ideas.