fpga4fun.com

You can use devcon.exe (download from Micro$oft) to switch quickly between the CyUSB and EzUSB drivers:

Echo Change to CyUSB driver
devcon update "C:\projects\xylo\StartupKit_Xylo-LM\USB drivers\CyUSB driver\CyUSB.inf" "USB\Vid_04b4&Pid_8614&Rev_0000"

To test if the correct driver is being used in a batch file:

devcon find *USB\VID_04B4*>drivestring.txt
findstr -i cyusb drivestring.txt>nul
if errorlevel 1 goto NoCyUSB

Excellent trick.
Just remember to run devcon from an administrator command prompt.

http://support.microsoft.com/kb/311272