I have a Dell Optiplex 780 with an Intel Core 2 Duo E8400 @ 3.00 GHz.
From the factory it was running XP Pro 32 bit.
I have updated the BIOS to A15, the latest version. I installed a new drive and installed W7 Pro x64. The machine runs fine with the original (2) 2G RAM chips.
I checked the Crucial.com website and ordered the chips their software tool that loads on your system recommended to add (2) 4G RAM chips to get 12 G RAM.
The machine has four slots, 2 with white tabs that have the original chips, and 2 with black tabs.
When I added the new chips to the black slots, on bootup the machine would only display a black screen. No cursor, no message about the amount of RAM changing, no beeps.
Next I removed the original chips and put the new chips in the white slots. Same result.
I then removed the new chips and put in the original chips.. and the machine boots fine.
OK, must be bad/wrong RAM chips, I figured. Lets go to 4allmemory.com and see what they tell us. Downloaded their tool, ordered those chips and had exactly the same "adventure".
What am I missing here?