Windows 7 - Unknown Wireless Connection Icon

Recently, I've re-imaged my computer back to factory settings. I've connected to my home's network, and everything was normal for a few days. And now, I have an odd icon in place of my wireless connection strength. I'm still connected to the internet (as I'm posting this), and I can still browse like normal. There has been some unreliability... Lately I've been monitoring my network usage with Task Manager and I'll go from the normal 1.8%-2.3% to 0% randomly, for random amounts of time. I'm not sure if the other two computers on the network share this problem, but it seems to be more with the connection itself than my laptop.
I don't know what this icon is, and even though it doesn't seem to be affecting my wireless performance, I'd like to know what it is and what it means.
I don't know what additional information I need, so if I do need to provide any more kindly tell me and I'll edit this post.

that is the icon for the wired lan connection.
It's simply telling you nothing is plugged into it.
You can get rid of the icon by disabling the lan device, but it's harmless and probably better if left on so it'll work if you ever plug a wired connection in.

We only have one wired connection, and that goes straight into our desktop. We don't have a router, so the rest of us just use the wireless from the modem.
How would I disable the LAN device?

control panel -> system -> device manager
find network adapters. Make sure you have the lan device and not your wireless card selected (shouldn't be hard to tell which is which) right click and disable.
To turn it back on just follow the same steps.
Make sure you do a proper shutdown next time you power down so the setting will save.

There's no LAN device under Network Adaptors, just my wireless card.

well that is definitely a lan icon.
I can't think of where it would hide other than under network adapters.

try right clicking the icon itself and going into the network and sharing center
on the right there will be an adapter settings link.
you should also be able to disable it by right clicking it there.

Only thing there is my modem...

I have to admit to being at a loss here.
there is no doubt that is a lan icon, I'm looking at one of them on my own screen right now.
I can't explain the lack of a lan device though.
laptop or desktop the system should have a lan port, pretty much all computers come with one minus some of the smaller netbooks/tablets.

Here's the device manager:

I believe you see the icon when the connectivity goes down to zero.
You may need to update the driver or at least go back to the driver version you where using before the re-imaging.