USB subsystem corrupted?

I recently installed some new USB devices on my system. I had problems with one of them (Windows said it couldn't find a driver), and I gave up on that after trying everything. A few weeks later, I went to use some USB devices that were previously working. Windows said that they, too, didn't have a driver. I went through the standard uninstall/reinstall of the drivers to no avail, trying different USB ports, etc. Only certain USB devices don't work, not all of them.

I decided to do a fresh install of Windows 7 on a spare hard drive on the same PC. I installed the drivers for the various USB devices, and they ALL worked, even the one that never worked before. So it's obviously not a problem with my PC or with the USB devices. I can boot back and forth between the two drives and find the devices failing on the old Windows, and working on the new Windows.

It seems like my USB subsystem has somehow become corrupted. Is there anything that can be done to "reset" its state back to new? I'm fine with losing all of my USB device drivers and reinstalling them. That will be much easier than reinstalling all of my apps on the fresh Windows 7 installation.

you could try this USB Driver Reset and USB Ports Power State Reset - Sysnative Forums

Thanks for the pointer. Unfortunately, that didn't have any effect.