http://www.sevenforums.com/tutorials/165554-usb-driver-general-fix-problems.html
General Fix for USB Driver Problems
I recommend using a wired mouse and keyboard,
removing all USB devices and in the
section where it says Uninstall all the
faded entries. take that as reading uninstall everything
USB, if you cannot get
hold of a wired mouse then you will have to follow the tutorial as written.
After going through this tutorial You may need to
reinstall some USB device drivers!!
After a USB device is installed and then removed
Windows hides the driver, this first part makes
all hidden drivers visible.
1. Unplug all USB devices except mouse and keyboard.
2. Click on Start orb, 
Type
Advanced System settings in the search box and Click on View Advanced
.System
Settings to go there.
3. Click on Advanced tab, Click on Environment Variables.
4. Under the window "System variables" Click on New.
5. Type devmgr_show_nonpresent_devices as the variable name and type 1 as the
value.
6. Click OK 3 times to close the windows.
7. Click on Start orb, Type
Device Manager in the search box and Click on Device Manager in the list
to go
there.
8. Click on View, then Show hidden devices.
9. You will now notice that you have a list of USB devices and that some lines
appear to be faded. Uninstall
all the faded entries.
The INFCACHE.1 file is used to store information
about USB drivers, the information in this file
may have become corrupted and
may cause windows to load the wrong driver or cause a driver
not found message
to be generated.
Deleting this file will force windows to generate a
new INFCACHE.1 file.
1. Right Click on Start orb and
Click on Open Windows Explorer.
2. Select Computer in the navigation pane, and search for INFCACHE.1
3. Right Click on the file INFCACHE.1 (if you have more instances of Windows
installed only do this
for INFCACHE.1 C:\Windows\System32\Driver Store)
4. Click on Properties, Click on Security tab, Click on Edit, Click on Add.
5. Type Administrators in the window with the blinking cursor, Click OK.
6. Delete the INFCACHE.1 file.
7. Connect a USB device, but not the one you were
having trouble with this will make a new INFCACHE.1
8. New Start the PC and try your device again.
NOTE... It may, in a few cases be necessary to go through this Tutorial two or
even three times to get this to work.