Getting blue screen when 2 ram chips in?

I am trying to repair my cousins PC and every so often the PC GETS a blue screen one blue screen said

BAD_POOL_CALLER (this was on the top top of the screen)

and on the bottom of the screen


Tech info:

0x000000C2 (then more codes in parenthesis)


I have also gotten the PC to get a blue screen that says Check your bios and does not list BAD POOL CALLER but does list new numbers on the bottom............is this just a generic blue screen?

Tech info:

STOP: 0x0000008E (0XC0000005, 0X8057019E, 0XAEE3F8F0, 0X00000000)

I am currently running MEMTEST-86
NO ERRORS

also the computer works ok if I take one RAM chip out doesnt matter which ram chip but it wont work with 2

any ideas?

I dont have any driver issues, I reformatted the PC

This is weird if 1 ram chip is in the pc works but 2 gives me the error