How to get USB-Serial hex back to Arduino UNO Rev3 / solved

Using Arduino Microcontrollers
16

I got:

C:\Documents and Settings\Owner\Desktop>md5sum Arduino-COMBINED-dfu-usbserial-atmega16u2-Uno-Rev3.hex
374845d004d03c6ca0535bb4b6f19235 *Arduino-COMBINED-dfu-usbserial-atmega16u2-Uno-Rev3.hex