i had an evdo usb device running internet in windows server 2003 it was working fine and i was using isa server 2000 with it to give internet to client pc

now i bought internet from another company who gave evdo usb the device is ZTE AC5710 which is working in strange way

i cannot run internet directly on server 2003 but isa is working fine clients and even i can access internet by setting proxy in firefox but IE, msn,yahoo wont connect even after giving proxy setting of isa server only firefox skype is working IE chrome,yahoo,msn are not working and internet is not running directly at all

i dont have any firewall on server2003 and previous evdo device was working fine so dont understand what the problem is can anybody tell how to fix this problem?