Hi I have the PICDEM USB Board (unaltered) and I have just downloaded and nearly successfully run the code for both the PIC (4550) and the PC (using VS2005). Everything when swimmingly right up to my second attempt to toggle one of the LEDs. I was able to turn on LED 3 but after that the software locked up and no further communication with the PICDEM board was allowed. I repeated the process and got the same result (I often try the same thing repeatedly and expect different results). Could this be a problem with Windows Vista? Has anyone else run this successfully on Vista?