can't boot with 3 beep code but can if wait a few mins

Hi I have a Alienware X51 (Early 2012), recently I got this problem that I can't boot it and it just does that 3 beeps code thing, but the tricky part is if I wait a few mins( say 10) then I can just boot it normally and it works, it's been months and the beeping is really annoying and I fear one day it will fail to work.   the only hardware change I did is trying to install SSD and I failed because the SSD was broken, I removed all the extra cables but there's one cable just stuck on the motherboard and I just can't unplug it, so I just left the cable there, with the other end hang in the air. i ran the hardware quick test and passed everything,  I recall the 3 beep code means motherboard failure,  any suggestions?