Connect an empty USB Storage Key to the Windows PC. Whether the USB Storage Key is not empty you will lose all the data inside it.
Run "BIOS USB Update" software.
Select from the list the inserted USB Storage Key.
Click on "Format for BIOS upgrade".
Confirm the operation clicking on "Yes".
The window shows the operation in progress.
Wait until it finished and click "OK".
Click on "Add BIOS" to save the BIOS file on the USB mass storage.
Select the firmware file from the explorer window and click "Open".
Wait until the software is writing the firmware on the USB Storage Key.
DO NOT REMOVE the USB key from the PC until this operation is terminated.
Click on "Finish" to close the software, then you can disconnect the USB Storage Key from the PC.
To upgrade the thin client BIOS using the USB Key follow the procedure explained at Booting from USB Key on generic Thin Client model.