it's no problem. just try to help.
i think i am out of ideas already. i have done many times of fresh installs (w7, w8) for this machine; i never had a problem using the fn keys, all of them.
for w8, i only install a very limited set of drivers; only 2 from ASUS:
1. atk package; and
2. elantech touchpad driver.
the rest are from manufacturers (intel chipset and RST; nvidia geforce; atheros LAN and WIFI; VIA). the system is working fine
😕