Alienware x51 continuos beeping

It can be a Harware failure 7 beeps means motherboard !

Hope some one with  more experience can come to your rescue soon, while that i recommend you unplug it from power and open the case and make sure everything is in place inside

Try to remove your memory and put it in back in place again, make sure they are any wires obstructing the Fans ect ect

Also this may help you

Sounds like a GPU failure. Power everything off and disconnect all power sources, including the monitor. Press the power button again to discharge any residual power in the system. Remove the case and remove, then re-insert the GPU. Reassemble and try again.

If that fails, go through the process again and use the on-board GPU (if your motherboard has) or swap another GPU (aka video card) to verify

Like Solrac said you should try reseating the memory and the GPU. Make sure it is not plugged into the wall when doing it.

Here are some beep code lists that can help you out:

 http://www.computerhope.com/beep.htm

http://www.technick.net/public/code/cp_dpage.php?aiocp_dp=guide_beep_codes

THANK YOU! I ALMOST HAD A HEART ATTACK.