Onboard Graphic Drivers

When you instal a new graphic card in a WinXP PC, you uninstal the original G/C driver so that the graphics then run on the default standard driver.
Later, after you instal the new G/C, you instal the new driver.

Question:
If you have onboard graphis in a new M/B, ie. Intel D865GLC, and you want to instal a AGP G/C, do you still have to uninstal the onboard graphic drivers first, or are the drivers automatically uninstalled/isolated when the PC detects new hardware.

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