I had an Arduino mega 2560, suddenly Arduino didn't recognize my computer and I thought the problem is about Atmega 16u2 and I decided to copy hex file from another Arduino Atmega 16u2 and paste to damaged Arduino but it didn't work. in fact, in our laboratory, we don't have any Linux and other software to reset or reprogram Atmega 16u2 on the other hand I know several methods to solve the problem but I need to know can I use the Arduino IDE to reset Atmega 16u2 without other software. thanks a lot.
Yes, you can recover the firmware in 16u2 only with Arduino IDE installed. In subfolder
hardware/arduino/avr/firmwares/atmegaxxu2/ of the IDE installation folder is the hex file of the firmware
Arduino-COMBINED-dfu-usbserial-atmega16u2-Mega2560-Rev3.hex. The README.txt file in that folder has sample command line to upload the firmware with avrdude.