I am a beginner and I am trying to connect my Arduino UNO with my computer.
When I am connecting USB the device in Device manager is listing as ATmega16u2 DFU instead of Arduino UNO.
And arduino.inf driver is also not installing.
Sounds like you got a board without the serial interface code on the 16u2 (is this an ebay/clone board?). I'd probably try using Atmel FLIP to upload Arduino COMBINED-dfu-usbserial-atmega16u2-Uno-Rev3.hex (located in (install location)/hardware/arduino/avr/firmwares/atmegaxxu2 ) to it.
I've never done this, though, so I can't say more in specific.