I just got my arduino uno and i installed the driver software as in the site.
When i open arduino.exe, it shows 'unable to open' and after some time, it opens.
Then when i try to select tools or open any example programs or do anything, it takes around half a minute to come.
Uploading time is also very slow.
I am using windows Vista.
If you went through Eried's suggestions OK then you do need to double check in Device Manager that the arduino is seen as the Uno R 3 and therefore is installed OK. Then go back to loading arduino and trying it. ALso it might be worthwhile completely uninstalling 1.02 and reinstalling it. I have it working on Vista just fine. If that still does not work, just try and install 0023 and see if it is any different.
I checked the device manager and its showing UNO R3. I tried 0023 and the same problem occurs.
This is my problem.
First when i select arduino application, this window comes. Arduino Forum
Then after some delay, about half a minute, this error comes. Arduino Forum
After i click OK, arduino window comes after some delay.
Then if i try to select tools, the tool window will appear only after sometime. Arduino Forum
The same problem occurs while opening example programs or while uploading programs to UNO or when i try to open the serial window. The delay is bit long. Actually the software is getting stuck.
I am sure that if you install and use this: http://arduino.cc/forum/index.php/topic,118440.0.html (do not launch the other arduino "official" files you have) your problems probably will fade away. The titlebar will say "Arduino ERW"