Download free windows 8 video drivers for dell optiplex gx520

my computer once install windows 8 it shows it needs videos drivers but when i install windows 7 the drivers are automatically there,what video drivers can i use for my windows 8.the make of my desktop is dell optiplex gx 520 please help me on thios one my email adress is chikojabchifundo@yahoo.com or chikojac@msb.mw