I have an old Dell Dimension 4300, on which I'm trying to upgrade the memory from 1x256 to 2x512 MB. The memory arctecture is SDRAN PC133. I have tried the two new memory modules together and seperatly and together in both slots. Every time I get 6 bleeps "8042 gate A20 cannot be toggled" and A green, B yellow, C green & D yellow.
I would be most grateful for any help. Its driving me up the wall.