Hi, just an update to my first post in this thread.
I still have the same problem. I tried to solve it by buying a dedicated USB controller card and a high quality USB cable and use this exclusively for the Virus, but still the same issue.
I've also noticed that for some of the parameters that do work (like OSC1 semi tone), a small dial (like a clock symbol) is showed momentarily in the lower right corner of the display. For some other parameters that do work (like Freq Shifter mix) a symbol resembling "SE" is shown in the lower right corner of the display. For the parameters that don't work (at lest half of all parameters), no indication is shown in the display that it has received any signal from my PC.
Very weird and frustrating. Anyone else have the same issue? Do I need to repair my Virus?