Arduino is Broken

I'm pretty sure my Arduino Uno is broken.  When I plug it in using the USB cable, the green power light turns on and the L light near pin 13 turns yellow.  They are the only lights that come on.  They do not blink.  They do not turn off.

Also, the Arduino IDE software on my Ubuntu 12.04 does not see the Arduino when I plug in the USB cable.  When I click on Tools from the IDE menu, the Serial Port entry is greyed out.  The same thing is true when I connect the Arduino to my Windows computer.  The IDE software in Windows has the Serial Port entry greyed out as well.

I tried resetting the Arduino by pressing the reset button.  Nothing happens.  I also hold down the reset button while plugging in power.  Again, nothing happens.

I did some research on the internet.  I think the problem is that either

1. the AT chip is bad or
2. the bootloader software on the chip got erased or corrupted and needs to be reloaded.

I found a page that talks about how to update the firmware on the Arduino.  Not sure if this will work but I'll have to give it a shot.