Matsonic ms9087c boot hang and beeps

Question

hello, i recently unstalled a new graphics card on my matsonic ms9087c board. now when i boot up the comp freezes and just keeps beeping. i shut it down and put back in the old graphics card and it does the same thing just beeps. i tried to reseat both cards, took out the ram sticks and moved them and set them back in, but the comp will not boot. i know it has to be an easy fix but i am now at my wits end with it! Help