USB controller going bad?

For the past 3-4 months, I have been having problems with what I believe to be my USB controller (not a gamepad, the IC on the mobo). I should mention now that I am using a USB WiFi adapter, specifically a Belkin Play USB Adapter. The first symptom was downloads in chrome randomly stopping; giving a "network error".

Then youtube videos restarting randomly or cutting to a green screen and rapidly skipping forward to the end of the video or just pausing and not being able to time-seek to any point in the video. All other video streams would give similar results.

Next, the WiFi signal strength tray icon would show limited access and show only the network I was connected to, instead of the usual list of ~7 I get. When I disconnect from the network, the icon changed to show a "ethernet disconnected" icon instead of the "networks available" icon. When I tried to open the network and sharing center via right click from the tray icon, nothing would happen. When I went through control panel to get there, the explorer window would freeze and crash. I went into device manager and my wifi adapter was not listed.

I tried to unplug and re-plug the adapter back in to the same USB port. Half the time this would work and return everything to normal, other times the computer would not recognize it; no "USB device connected" sound, nothing new in device manager, nothing. Sometimes if I tried a different USB port it would work until it did the same thing and then I neither port would recognize it. I should note that this symptom (the one described in this and the previous paragraph) usually only happens with high internet traffic; ~2-3MBps download and 700+ MBps upload.

I tried a different USB WiFi adapter; a Netgear N300 with the exact same results.

The next symptom is devices, specifically an xbox 360 controller, iPod, and Google Nexus 7 randomly disconnecting and then immediately reconnecting with windows giving me a message balloon saying "this device can perform faster if connected to a USB 2.0 port. " I know all of my ports are USB 2.0, and 2 more from a second controller on my mobo being 3.0; and yes, I tried plugging my WiFi adapter into those as well, same result.

Just recently while playing farcry 3, the screen froze and audio looped and then ended. After restarting my pc, the same "ethernet disconnected" icon was in the system tray. I could open network and sharing center this time and then clicked "change adapter settings." My WIFi adapter was not listed, just my ethernet port and the VMware adapters for VMware player. Another restart with the adapter removed and the re-connected after windows had finished booting returned internet connectivity.

My PC specs are:
Windows 7 Ultimate x64
Asus Cross Hair IV Formula
AMD Phenom II X6 1090T
8GB Gskill ripjaws PC1333
2x AMD Radeon HD 5870
1TB Seagate barracuda
1TB Samsung spinpoint
ASUS DRW-24B1ST 24x DVD burner

Any help would be appreciated. I'm tired of having to download every file onto my nexus 7 and then copying it to my pc.

Thanks in advance.

Can you install an add-in PCI card that gives you USB ports and see if those work for you? This is how I determine if the onboard USB is going bad...