Brand Brand New User

I am a new Uno user. I have the Blink Sketch working. I then accessed the sketch and modified the delay values. I then went to tools > Board and the Uno board was selected. When I went to Serial Port there were no choices. I then went to file upload and got the following error message Serial Port 'Com 1' not found. Did you select the right one from the Tools > Serial Port Menu? I am using W 7 and Arduino 1.04. Thanks for any and all help

I found that when my Uno disappears like that, it comes back if I bounce my laptop....

http://arduino.cc/forum/index.php/topic,118440.0.html