The contents of the obsoleted AN2131 DVK are included in the CY3681 FX2 Development Kit. They will be present in the default path C:\Cypress\USB after downloading and installing EZ-USB_devtools_version_261700.zip from this link in its default directory.
Examples - C:\Cypress\USB\Examples\EzUsb
Doc - C:\Cypress\USB\doc\EZ-USB Series 2100
Drivers - C:\Cypress\USB\Drivers
Hardware - C:\Cypress\USB\Hardware\EZ-USB Series 2100
Ez USB Control Panel- C:\Cypress\USB\bin
Please not that EZUSB.sys is no longer supported. We recommend the usage of our generic USB driver CyUSB.sys as well as our set of software development tools SuiteUSB available for download here.