Tell us what is the brand of your modem, type etc.

My ancient Huawei E220 3G modem does not have any 64bit driver by default.
I went to download the firmware from Huawei website and upgraded it, although it only comes with Vista 64bit driver but IT'S still working on Windows 7 x64 flawlessly, until now.

This post has been edited by 1024kbps: Jan 8 2012, 06:06 PM

This? http://huaweifirmware.blogspot.com/2011/05/huawei-e156.html
Not sure if its the same model,
You should just download the driver only, since upgrade the firmware will erase anything on that 3g modem, and you wont be able to use it anymore unless you noted down that number(*99***16# or something, each ISP will have different number iirc) that use to connect to the ISP.