I am having a problem with my USB midi interface, a midiman midisport 4x4. I have 2 gigastudio PCs and have had thye same problem with both. They have different CPUs, both have 520 meg Ram, one is SCSI one Ultra ATA. The problem is one of loud clicking thru audio when the midisport is connected. Detach the USB and no problem. One machine has Gina analog outs, the other has Digi96 lightpipe outs. The clicks register as overload on my protools interface.