It is defintively a memory problem. Is the first memory stick set closest to the CPU? Are the memory sticks the right type. Since you have a pIII 866 you must have PC133 SDRAM with a 6.5 multiplier setting. If you placed PC100, nothing will work. If you cannot get to the BIOS, it is because there is no binding between the mobo and the RAM. Check to make sure you have PC133 and no PC100, with memory stick set in right place.