zigly

I have a 4.1 system which i managed to blow out the sub on. I have since gotten a laptop that does not support 4.1 and am looking into picking up a 2.1 system. What im curious about is whether I can just get a 2.1 sub and use 2 of my old 4.1 speakers and the control unit. Would the control unit from the 4.1 be compatible w/ the 2.1 sub unit?? thanks