Megaworks 510D Speakers crackling when vol. raised

I've had a set of Megaworks 510D 5.1 Digital (Multipole connector) speakers for a little over a year now. When I upgraded my computer a few months ago (PSU/Motherboard/CPU) and started it back up I've been experiencing an awful distortion that sounds like the television when it loses signal and gets only static. The problem will only occur when I adjust the volume knob past a little under 1/2 it's turning radius (with 100% volume set in software controls). The higher the volume of sound being played the more distortion, and it easily reaches the point of being completely static when set to anything over 1/2 the radius.

I asked the support team at Creative and they suggested it was interference, but adjusting the position of the subwoofer and speakers has no effect. Any ideas on how I can diagnose or fix the problem?

I am 100% sure there is crystal clear quality until a certain volume has been reached. It's not the control either, since the sound is distorted according to the volume of individual sounds.

I've tried that and it doesn't work. I'm using an Audigy 2 ZS. My headphones work perfectly at any volume, so it must be the speakers. I just tested it again and even the subwoofer crackles.

Yeah, it's just the speakers. I'm wondering if they just got shamboozled by a lightning storm or something. I've tried a different cable to connect it, switching speakers around, using only 1 speaker, testing the subwoofer alone, moving it, turning off the monitor, switching the slot the sound card is in, playing with settings, etc. It's highly unfortunate, but I may have to just get new speakers eventually.