ei, this is quite similar with this thread problem with BL-U80G (Ralink RT7x/RT257x chipset)
my Ralink R73 perfectly split/shared my LAN connection (DSL connection) when i used XP however when i changed my OS, had a clean install of the OS, and used the original installer of the driver, is failed to split/share the connection.
i installed and tried many old and recent installer for RALINK access point utility, dis some installing and installing of the driver, and other possible remedies (whom i think was good remedies) to solve this issue.
i read its original poster of such thread solved his connection issue but it boiled down by not identifying the real meat of the issue - by giving the exact solution.
hope that computer techies and windows 7 geeks could help me solve this connection issue.
THANK YOU VERY MUCH!
BTW: mine is not a chipset, it is a USB type. The OS have identified it as R73.