Hi Rich,

You can use the internal oscillator for pretty much everything except the USB
peripheral. This requires XT, HS or EC type external crystals/oscillators.

If you have a breadboard, I would drop the USB PIC on it, and wire up the minimum parts
needed to get a USB connection up & going. If it works, then you have it narrowed down
to a problem on the other board.

Also, if you had USB working before, and it stopped working after you added a few other
components to the board, you might try removing some of the other ICs to see if it starts
working again.