What does it mean if my computer turns on and beeps and hen doesn't do anything?

I'm using my other computer to write this question...I can't get my other computer to work. I recently put some new RAM in it and since then, when I put my computer on, it just beeps and then doles nothing, just keeps beeping and the monitor doesn't come on or anything. Any suggestions as to why this has happened would be great and even better if there's a good way of fixing it, thanks :-)