Install National Instrument GPIB-USB-HS Drivers. ( I used "ni488222.exe")
Install Agilent I/O Libraries. ( I used "Iolibs_k_01_00_00.exe" )
Run I/O config : Auto config
Remove all configured interface except GPIB0.
Rename GPIB0 to hpib7 ( it may work if you keep the name as is but this is the way I did it )
In Hp Basic AUTOST :
LOAD BIN "HPIBS;DEV hpib7"
There you go, it works!
for additional info: