Have you installed a 64-bit version of Java 7? I think there is incompatibility with the native libraries shipped with Processing. Try a 32-bit version.
Note that on the Oracle site, Java 7 is still flagged as "for programmers only", ie. they don't think it is suitable already for general public usage. Well, we are programmers, but I thought it was worth mentioning...
(Still using Java 1.6 at home.)

It was the 32 bit and has been removed.
Which Java 1.6? There are 31 or so.
Mine may have been 11. Tried out 31 and it isn't working.
If you know any of the following please share:
version of java, folder, path, windows path settings, windows environment variable, processing configure file or menu.

The latest 1.6, I regularly do the updates.
Reading again your message, I am not sure, as I don't use "emulator, phone devices" and I rarely export applets with OpenGL (if ever), but often people have issues with the latter. I never recall if you must sign your exported jar. Where they working with your old PC?

Yes it was working on the same machine. It is the same imaged backup as well.
Exporting was working to the phone straight out of Processing with no signing.
It was not checked if it could export as an applet.
Even though 7 was removed when an Applet is loading a status bar by Java is displaying files loading.
Is this specific to 7 or was that an update in 6?