Just follow the below few steps to configure Windows Vista O/S:-

STEP 1: Automatic Configuration
- Insert the Huawei CD into disc driver
-Follow the same procedure as for Window XP
-Make sure no USB cable plugged into the Computer
-At the end it will show you that the configuration. has been successfully completed.
-Click “FINISH”

STEP 2: Manual Configuration (Installation Of Modem/Port)
-Go to start, settings, then Open “Control Panel”
-Connect the modem to the Computer
-Click Add Hardware
-Follow the steps of adding new hardware as usual Manually not Automatic as Recommended
-Select port from the list, click next
-After finish port installation
-Start again to Click Add Hardware
-Select huawei modem from the list
-Then “Click Next” Follow the wizards to the end of installation.
-If you to check modem or Port
-Go to my computer, light click select Manage
-Double click Device manager
-Find and maximize modem or Port (check if driver working properly or not)
-If not working try it again.