Strange speaker noise from new build pc

Hello,
so my problem is that my speaker has no other sound but a strange noise when i plug it into my new build pc(front or rear jack), its a cm elite 311 casing, asrock h77m mobo and running windows 7 64bit.

i tried the speaker on my macbook and it worked just fine. i also reformatted my windows but the sound are still there.

i plugged in another old speaker to the pc and it also has the same problem(strange noise).

is it the motherboard audio jack or somewhat are causing this? the speaker was working fine on the new build pc before(using intel hd graphic) and after a long day i was messing with the graphic card (some problem) and finally get the graphic card to work then when i turn on my pc again it has this problem... it is really frustrating and double face palm... would buying a cheap external sound card fix this? pls help anyone?