How to install bsnl nic card u100 driver in my w7-64 bit

Can't find the manufacturer for this product, but if you check the web site for them, try using Vistra drivers. Or possibly download the XP drivers, and extract them using a good compression software like 7Zip (WinZip and Windows tend not to be able to extract some .exe files), then point Windows 7 manually to the files when it asks for the drivers.