Which model Vivobook?
If it is fairly new it is unlikely that it has Windows 7 drivers available even if you could install 7 on it, which could be an issue if you are using USB 3 ports (blue) since W7 has no native USB 3 support. You would need to slipstream W7 USB 3 drivers into the install image, but then you still would not have drivers for the devices if ASUS doesn't have them on the product support page.