Well when i bought my computer it came with 2 1gb ram cards installed and it was working perfectly. That was about a year ago and now the monitor had stopped working. when we take out 1 ram card doesnt matter which one or which slot it is in the monitor works again. We have tested the each individually and in each slot and the ram cards both work perfectly. But when we put both in at the same time it stops working. The ram cards are PC2 6400 platinum editions The graphics ard is Nvidia geforce 8800 GT The motherboard is AMD Athalon 64 X2 dual Also as a side not the mother board appears to have 4 slots for the ram cards 2 yello and 2 black. The yellow ones are where the ram cards were originally installed and the clips for the black ones are bigger than the yellow one's. When both ram cards are in the black slots the computer works but gets the blue screen of death every now and then and microsoft support said there might be hardware failure causing it. So i am pretty sure they dont belong in the black slots and when in the yellow slots the monitor doesn't work but they used to work in there.