Can uploading code harm an Arduino Leonardo board?

Okay, first off, I'm new here, teaching myself C, and am not sure what's going wrong - which is why I'm posting my situation here.

I have an Arduino Leonardo board and have uploaded my sketches many times with no problems. Earlier this week I uploaded new code and immediately after uploading the code the Arduino disappears from the computer (Windows 7) and I get this message "USB Device Not Recognize". In Windows 7 device manager, the only listing I see is "Unknown Device". I've tried updating the driver, uninstalling/reinstalling the driver - each time pointing to the Arduino Driver folder. Each time the result is the same - "The Best Driver software for your device is already installed". I've tried all the other USB ports - same problem. I've tried rebooting the computer - same problem. Pressed the "reset" button on the Arduino - same problem. There is also nothing listed under "PORTS" in the device manager and the "tools/serial port" Arduino menu option is ghosted out. I've always kept the Arduino in it's original packaging when not in use. I can't imagine something went wrong with it.

I contacted the place where I purchased the Arduino and they kindly sent me a replacement with no questions. When I hooked up the new board, the computer saw it fine. Everything looked good to go. I then uploaded my code and suddenly the Arduino disappears from the computer and I get the same message "USB Device Not Recognize". Nothing listed in the ports - same issue as before.

Which leads me to my question - can uploading code harm an Arduino Leonardo board? Is there a way to restore the Arduino?

Thanks in advance!

Try this. Hold down the reset button on the Leonardo. With your other hand upload a different sketch (eg. the Blink one). When it starts to say "uploading" release the reset button.

The problem is that the windows 7 computer can't see the board. There is no COM port. It's only listed as an "unknown device". Pushing the reset button makes even that go away. I'm using an Arduino Leonardo board. My only option it seems like is to re-upload a bootloader. Found some stuff here...

Looks like I'll need to make a cable...

Problem is, I don't really know what in my code caused my Arduino to loose it's bootloader in the first place.

Help!

SOLVED!!!

Thanks to this post...

http://arduino.cc/forum/index.php/topic,145143.0.html

This made using the reset button and uploading the blink sketch (as Nick suggested) make more sense.

Thanks guys!

THANK YOU!
I thought I was going to have to get another Leo to reburn the bootloader but thanx to you Leonardo is working again!!!