I found some info on loading. Thanks Coding_Badly, I'll try that when I get some time. I AM curious...

Do you have any procedure for reloading that chip? Mine is a Mega16U2.

No insertion sound is heard. Windows doesn't seem to sense it at all. I've got Newark sending me another unit, so I'll find out if the one I have is just a dead one. Assuming I won't get unlucky twice.

I just received from Newark (Element14) my first UNO Rev3 unit. I cannot get my computer to sense or recognize it, meaning it doesn't show up in device manager anywhere after powering up, nor as an 'installing device' message balloon. Actually, I have tried 2 WIN7 and 1 XP machines, and 2 different USB cables (both of which worked on printers). None of the machines sensed the UNO when I plugged in the USB cable. Since Windows didn't sense them, I tried to force installation of the device driver on a WIN7 64bit machine, but after doing so Windows reported a Code 10 error, and that the device was not working. (I had previously downloaded the arduino-1.0.3-windows software and used the driver folder as the target for the driver.)

The UNO unit shows a lit green power LED, and the pin13 LED blinks rapidly and sporatically for about 5 seconds and then settles in to an ON/OFF period of about 1 second (half on, half off).

Any thoughts? Thank you for your help.