Hi Guys,
I have google about this one, but i don’t find any related topics about this issue.
Actually I have buy new one arduino uno R3 yesterday.
When I connect it to my PC, The “L” led is not blinking, i think it should blinking
I have try to connect it to my mac and windows its not detected as arduino or usbmodem but detected as Atmega.
Any suggest to solve this issue?
Is it possible my arduino is broken? 
(bad News :~ )
Oh yeah, i have try to update my FTDI but still no luck :(
ferland: When I connect it to my PC, The "L" led is not blinking, i think it should blinking
Not at all? Mine blinks briefly when powered on.
Yup, is not blinking at all. But the L led and power is on. Any suggest?
If you disconnect the power, and reconnect it, does the "L" LED blink at all? Or go straight on?
It go straight not blinking, i have try push reset button too. Still no luck. :(. My pc still cannot recognize the arduino, it detected as atmega :(
Nick do you have any idea about this?
Or anyone who have faces this issue please help me 
Is it a real Uno, or a clone? A clone may not be bootloaded.
I think its not clone cause i got the package, sticker and thank you paper. I have googling about the fake one but, i think is real one since i buy original from italy. If the bootloader is not installed, whats i supposed to do?
1) Return it to the source and request a working board. 2) Buy a bootloaded chip http://www.dipmicro.com/store/CPU-ARD328P other sources also available 3) Buy a tool that will allow you to bootload. I used this one for a long time http://www.mdfly.com/index.php?main_page=product_info&cPath=5&products_id=415 before I get this one to use with larger chips http://www.mouser.com/ProductDetail/Atmel/ATAVRISP2/?qs=%2fha2pyFadujqFzV%252bExzQOlFEGuFbE5zkYm9OzGvRqkjeoy23MLFzjw%3d%3d Many others exist also.
So do you think my arduino doesn't have a bootloader? Do you have any tutorial for this?
There are several - but you need a tool to load one - see #3 - or a working arduino that you can load an ISP sketch into t hat will burn a bootloader, here's one of the best guides on that. http://www.gammon.com.au/forum/?id=11635
ferland:
It go straight not blinking, i have try push reset button too. Still no luck.
:(. My pc still cannot recognize the arduino, it detected as atmega
What do you mean “it detected as atmega” exactly?
I mean the computer recognize my arduino as ATMEGA device not arduino, i think its supposed to be detected as arduino nick. :) Cross roads told me that my arduino need to add bootloader cause the L led is not blinking. Do you have any idea about this nick?
Can you take a screenshot? An Arduino has an Atmega processor.