install problems

Hi, I am using Windows7 64bit OS.
I am having problems getting Arduino Duemilanova to install, It goes though the install ok and tells me it was successful, but when I try to open it , I am getting an error message from the Java virtual machine launcher. could not find the main class processing.app.base. Program will close.
I have just done a reinstall of windows, this did work before that. Ernie

What version of Arduino IDE are you using? After your re-install of Windows (Or did you restore from a restore point?), did you download and re-install the Arduino IDE, or did you restore it from a backup?

Hi,
thanks for the reply.
I am using ver oo23, windows was a new install, the IDE was from a backup. Ernie

Hi, I have found the problem, seems as though there were folders missing, downloaded IDE again and all was fine. Thanks Ernie