Default internet pass through connected but not working

hi
i have htc desire s, which has installed official ICS ....
in my pc i have installed latest htc sync and installed all required drivers....
i have installed windows 7 64 bit in my pc....
when i connect my phone to pc , and select internet pass through .....
in notification it is connected but it is working for just some seconds it is about 10 to 15 seconds ....
then i can not use internet using internet pass though in my phone........
so please help.....