Need help trying to repair my Logitech x-540 system, offering 20 dollars for help

Ok so I just moved across the world to New Zealand and I shipped pretty much all of my computer supplies. I went and took out my Logitech x-540 speakers and set them up, the only problem is that no sound whatsoever comes out of them. The wired remote console thingy gets power and when I turn on the system you can hear a slight brief hum from the subwoofer (which is normal) indicating the speaker has gotten power. But like I said, there is no sound coming from any of the satellites or the subwoofer.

In the x-540 system, the subwoofer houses all of the actual receiver components and I am trying to open it up just to see if something was blow something or if there is obvious damage to the circuit board. The only problem is I can't figure out how to take the thing apart. i can take the actual speaker out of the box no problem, but taking out the back panel is giving me a pain in the ass since the power cord runs through the panel and is hot glued on the inside of the box. I can't really explain it well enough but I took pictures to try and illustrate my problem.

So basically:

http://i45.tinypic.com/9tljz9.jpg

Here is the back panel, as you can see the power chord runs through the panel that I am trying to take off. It is held in place to the panel by some sort of stopper thingy (you can see that I have scratched it because I've been ramming it with my keys to try and open it up). I don't know how to take that stopper off so I can remove the panel completely. (my terminology is terrible, forgive me)

http://i47.tinypic.com/w81476.jpg

Here is the inside of the subwoofer box looking through the hole that the speaker occupies. As you can see the other side of the power cable is hot glued to the back panel.

So I need some advice for taking this back panel off without having to cut the power cable (I have no way of reattaching it right now without the help of someone who knows about electronics better than me). Whoever can walk me through getting the back panel off I will send ten dollars through paypal to. Whoever can troubleshoot my problem with no sound and whether the problem lies on the circuit board will be given ten dollars.

If you guys have any questions please ask. I just spent 50 dollars shipping these speakers around the world and I don't want them to just go to waste like this.

That is a plastic power cord grommet designed to grip the cord tightly in place to avoid the cord being pulled out and detached from what it's soldered to. I've had success on a couple occasions getting them out without damaging them so they can be reused, but it can be very difficult. First try and remove the glue around the grommet itself on the inside. The sliding tab that locks into place is on the outside though, highlighted by the single yellow arrow on the bottom of the grommet here:

http://img51.imageshack.us/img51/5117/9tljz9cr.jpg

You could try softening the cord a bit with a hair dryer if you have one, though JUST SOFTEN it, DO NOT get it hot enough to melt. Then take something like some channel locks and try to grip the grommet tightly where the yellow arrows are and compress it far enough to allow pushing it through to the inside of the box.

If that fails, you can remove it by destroying it's outer grommet lip via taking a single edged razor blade and carefully rocking it downward (toward the box) back and forth where the green line is. You can then reinsert it and seal it up with black silicone or try and find a suitable replacement. You can even fashion a makeshift grommet with just silicone, but it won't be as strong.

Keep in mind you mainly want to keep the grommet capable of A) gripping the cord, and B) resisting pulling out the back of the box. Thus it's inner lip is the important one, not the outer.