Speaker popping and dead sub

Hello, I have a pretty old setup in my apartment. It has served me well for almost ten years probably, but now I am starting to have issues. A few months back I noticed I would get an occasional popping sound from my speakers, usually a minute after turning on my system. It usually pops once and then the speakers work great. sometimes it pops after being on for awhile. sometimes it doesn't pop at all. I decided the other day to run the test tone to make sure they all work and the speakers all passed the test. Only problem now, is my subwoofer doesn't work anymore. It's almost like the test tone screwed it up or something. If the sub is turned off and I plug it in, all I get is a humming sound and a very slight burnt smell coming from the sub. It doesn't matter if I turn it on or off, same affect. Does the same thing if it is plugged into my receiver or not as well.

Any ideas would be greatly appreciated, thanks.

I am using a Sony STR-DE675 Receiver
My speakers are Cambridge Soundworks movieworks
My sub is a Cambridge Soundworks Basscube 10S

Thanks for the reply, I know this is old. I got really busy and haven't had a chance to take a look at the sub. I went to my parent's house today and they have the same sub and the same problem. they probably got theirs a year after I got mine.

I took the plate off and upon a quick inspection I did not see any visual signs of burning but it did have a burnt smell. After the Rangers game I will spend a little more time with it.

Anybody have any issues like this with this sub?

thanks