Some questions:
- which software is running on the PIC?  What it does? We need some more 
information to help you...
- how you determine that the PIC is not working?
- are you using an oscillator or a resonator? The question is not 
trivial because in accordance with the datasheet you can use a resonator 
but seems that none is able to do it. You NEED an oscillator. (I'm now a 
little polemic with microchip for this...)
Cheers
         Nicola


Tamas Rudnai wrote:
> Added [PIC] tag so everybody have a chance to see this message.
>
> ---------- Forwarded message ----------
> From: Mujahidin <iddhien@gmail.com>
> Date: Jun 16, 2007 3:31 AM
> Subject: Problem with PIC18F4550
> To: piclist@mit.edu
>
> Does anyone know with my problem??, I'm using PIC18F4550 to emulating RS-232
> over USB, Now, sometime my system good working and sometime stop working. In
> the first minute is good working and on the 10 next minute the system is
> sometime stop working. I'm using recommended schematic on the
> http://pic18fusb.online.fr/wiki/wikka.php?wakka=WikiHome . Please help me..
> And share your knowledge for me. thanks very much..
>
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