Secondary drive 0 not found

I have a dell demension 2400 series desktop that had only 256 memory. I installed (2) 512 sticks of memory, now my computer says "secondary drive 0 not found." secondary drive 1 not found." press f1 to continue or f2 for setup utility. When I press f1 everything is ok. f2 does not open. What is wrong? How can I fix this problem?

I dont know much about computers but did you get the right ram sticks that will work for your computer.