HELP! PUT THE RAM IN ANOTHER SLOT........

YESTERDAY I WAS TRYING TO CLEAN THE INSIDE OF MY COMPUTER. ONCE I DID THAT I TOOK THE RAM MEMORY CARD AND PUT IT IN ANOTHER SLOT. WHEN I PUT EVERYTHING BACK TOGETHER, I TURN ON THE COMPUTER AND JUST GOT THIS BLACK SCREEN ON THE MONITOR AND ONE OF THE KEYBOARD LIGHT WAS BLINKING. I WENT TO A LOT OF WEBSITE TRYING TO FIGURE OUT HOW TO FIX THIS PROBLEM AND DIDN'T HAVE NO LUCK YET. I ALREADY TRIED TO PUT OUT THE PCI CARDS AND THE DVD DRIVE OUT, BUT I GET THE SAME THING "THE BLACK SCREEN ON THE MONITOR". I DID THE 30SECOND HOLDING THE POWER BUTTON AND IT STILL DIDN'T DO NOTHING. CAN ANYONE PLEASE!!!!!!!!!! HELP ME FIGURE OUT THIS PROBLEM. I GOT A DELL PC, BUT A DIFFERENT MOTHERBOARD, AND ITS RUNNING COMPAQ.