8 gb ram only 4 recognized

A friend of mine bought a refurbished computer, with 2 sticks of 4 gb memory, total of 8 gb.

From the get go it only registered as 4, we tried both sticks, simultaneously in a different computer, and they both registered, total 8 gb.

He went to a computer technician, and he said, many times, if the two ram sticks are not identical, there can be a problem, he wrote to the seller, and received 2 new ram sticks. He put them into the computer, and only 4 gb registered, at one time after putting them in, they both registered, but after a restart, we were back to 4 gb.

The operating system is windows 7 professional 64 bit.

Let me just point out, the computer doesn’t even show 8 gb, just 4 (not like others that had a problem of 8 gb, and only 4 gb usable)

Any help would be greatly appreciated.

okay, sorry for the delay, we experimented with what you wrote. it took a while to find all the variables.
it looks like thrashzone hit it on the button, that there is a faulty ram slot.

we checked the bios and it registered only 4 gb ram.
we tried putting in 2 2 gb ram, and it registered only one of them.
we tried putting in one 4 gb ram in the second slot, and it did not register at all, only when when we put it in the inner slot.
we also tried an identical laptop computer, and only in the outer slot, and no problem, and when we put in 2 x 4 gb, it registered 8 gb.

so it seems to be a physical problem.

thank you very much for the help.