Currently I am using a Compaq Presario M2000. It came with a 256 meg ram card installed and I installed 512mb card over a year ago. It shows 638 mb of ram in the system properties leading me to believe it was only a 128 card, although it still is labeled 256. anyway thats not my problem. Everywhere i checked it says the computer can handle two 512mb chips . I bought another 512 mb piece of ram and installed it inplace of the original 256 to give myself two 512 mb pieces.
when i turn on the pc i get two loud pc beeps and a black screen. I tried numerous combinations but the only way i can get the system to work is with the 256 card in SLOT 1 and either of the two 512mb cards in slot two. they both work in slot two but neither work in slot ONE. whats going on?? I really need more ram to run programs which I use for drafting, and a new pc is out of the question, money is tight. Anyone know whats GOIN on??Is this site any help?

http://h10025.www1.hp.com/ewfrf/wc/product?product=433559&lc=en&cc=uk&dlc=en&lang=en&cc=uktried some things on the link but nothing seems to work. the thing is both 512s work in port NUMBER 2 when they are interchanged, so I know both cards are properly functioning. But as soon as I remove that 256 from port 1, I install either of the 512s and when I power up I get two beeps and a BLANK screen.Is it correct type of RAM? Where did you get it from?Its the same type of ram with all the specs of the 256 in slot 1. the 512s work fine in slot 2 which is what confuses the *censored* out of me. I bought it online so returning it is basically out of the question.Have you tried using only 1 512 in Slot1 and seeing if it will boot properly ? ?
Double-checked the BIOS settings for RAM setups ? ?
Use a can of compressed air to blow out the RAM slots in case there's some dust in there ?