The U706 is a plug-and-play device in 90% of cases. It uses the standard (hidusb.sys). This means that when you first plug it in, Windows automatically installs a basic driver that supports:
This is a mapping issue, not a driver problem. u706 joystick driver upd
If the driver doesn't help, the U706 is known for thin internal wiring. Sometimes the "driver issue" is actually a loose connection inside the casing. The U706 is a plug-and-play device in 90% of cases