badge, I suspect the original model number may be incorrect.
I did not find a P5GP-1 either, but I did find a P5GPl.
That is why I posted the info so taheriyan_r could make his own selections.
If nothing else, he can use the ASUS Navigation Wizard.
I googled the MB number He gave and it came back to Chinese links. I looked at the ASUS 'search' briefly and did not see the board listed there. It's possible the board was used by a system builder, was made by ASUS, and given a 'different' model number unique to the builder. It must be very old.