step1

"enter device manager "

step2

select "Decision PCCOM PCI 2 PORT"

step3

select "Port Configurarion"

step4

select the COM port which you want to start from "starting COM".

step5

Reset the compter first. Please note: do not execute "computer hardware scan" before reset the computer. After the computer is reseted, the computer will auto select the COM port that you choose in before.