why can,t i find motherboard to case usb
Ummm... what? Your question makes as much sense as 'Where can I find the cheapest flux capasator? Lowes or Home Depot?'
What Mobo, What case and exactly what are you trying to accomplish. Answer these questions in a new thread with a title that represents those facts and you'll get a better response from somebody around here likely to be able to help you.