Cannot find mobile broadband device

When i got my dell of a friend, i installed all other drivers as i reset it to windows xp, then when i tried installing the mobile broadband driver and it says "device could not be detected, installtion aborted. When i installed another driver which was the utitlity for another country to just test and it installed but when i ran it it says "no device detected" and i have got a sim card plugged it. Can someone please help me i really want to use my mobile broadband on my laptop, please help ASAP