Thanks for the reply. I have un-installed and re-installed. I have restarted my computer... I have even crossed my fingers.
On Mac I click download, and when the download is complete I can open the IDE. I have moved it into my Applications folder and it launches as soon as I click on it. There is no way I can see for that to go wrong.
On PC, it downloads a zip and there is an install "process". I have never had a problem with Arduino and PC (other than a lack of coding knowledge).
Could it be a Java thing by chance? I will update to the latest Java, uninstall and reinstall the IDE and see what comes of this.
EDIT: does it matter that I am on "Mavericks" OSX 10.9.1?
Thanks again. When I try the "Blink" example this is what I get:
Blink.ino:10:21: error: Arduino.h: No such file or directory
Blink.ino: In function 'void setup()':
Blink:15: error: 'OUTPUT' was not declared in this scope
Blink:15: error: 'pinMode' was not declared in this scope
Blink.ino: In function 'void loop()':
Blink:20: error: 'HIGH' was not declared in this scope
Blink:20: error: 'digitalWrite' was not declared in this scope
Blink:21: error: 'delay' was not declared in this scope
Blink:22: error: 'LOW' was not declared in this scope
Anyone here know someone I can PM for help? It would be nice to use my working computer. Arduino is the only thing that I need Windows for. I would rather not fire up another computer if possible.
I was able to compile code with an install of "Nightly Builds" IDE. Does this tidbit help diagnose the problem?