In an attempt to get a WD USB HDD to work I followed a suggestion to uninstall all devices of type Mass Storage using USBDeview. Now, Windows 7 does not show any mass storage device, even the ones that worked previously. For example, a connected USB pen drive is listed in USBDeview as not connected:
In the Device Manager it appears with an exclamation mark:
It is not shown at all in Disk Managment.
I already tried reinstalling my ThinkPad T420si's Intel chipset drivers, but to no avail.
How do I get USB mass storage to work again?