Tinsaafi has hit the nail on the head. Its just possible that you fried (or it was fried anyway) the memory sticks as you put them in. ESD is a major cause of component failure in these cases.
While 133KHz memory will work in a 100KHz system, 66 wont work in a 100 or 133 and 100 wont work in a 133 (still following me?)
When you pull the sticks out (after first putting your hand on the Power supply box to ground yourself - you will be wearing rubber soled shoes wont you
) check if there is a label on them. you should get a speed reading on it. If it isnt clear post as good a representation of what is written on the stick here or mail me.