Reply to Vci 100se freece's time to time

My vci freeces ocassionally when i am using fader fx whit jog wheel tractor work's good even if vci stop's working,problem goes away if i take usb off and reinstal it. Have i but my usb in wrong port or does it depend?

i have ni audio dj 8 sound card acer extensa 5630 Intel Pentium dual cpu t3400 @2.16ghz 2.17ghz , 4.00 gt ram windows vista home premium.

and also i get click's to audio when i press shift button.