New Speakers, New Laptop yet my speakers are cracking need help please?

I purchased an Acer Aspire 7745 g series laptop 2 days ago. Along with this laptop I purchased Amadeus home surround sound speakers. I got 4 speakers (2 front and 2 rear) along with a subwoofer. I needed to by a converter for my audio jack since I had 2 cables that needed to be plugged into the laptop and only had 1 audio jack. The first day it worked perfectly fine. The next day i started to get crackling in my rear speakers that are mounted to my wall. I have re-wired everything twice to make sure they are all in properly. I switched my sound to 5.1 speakers in control panel also. PLEASE HELP!!!