First,Chick your G400 Graphics card's SN

Like this: G4+MMDH4A32G

and must be have AGP mainbord.

If it had "4A",that means it can work in

AGP4X.

Then uninstall the drivers before 5.50.

Then reboot,the windows will found the

standard display card,use the windows

drivers.

Reboot again.....

Than install the drivers, must be 5.52 after

then reboot again ,that you can see the

AGP 4X in useing......