how to disable built in Video card

[bandit1969]

I've just bought a ATI Sapphire radeon 9550 256MB for my Packard Bell i-media 2411. With Quaser (MS6786) motherboard.
Before installation. I know that I have to disable the built in video card(VIA/S3G KM400/KN400) via the BIOS first. Problem is I don't know where to go in BIOS to do this.
The only thing I've found is in the Advanced chipset features, a AGP Driving control that can be set from Auto to Manual. Whatever that is???
I'm not very computer minded, my skills have been limited to upgrading RAM before this.
Can anyone help???

Or am I making too much of it should I just plug the card in the AGP slot and install the drivers??

[edwin]

I think you should power down, put in the card and power up with the monitor attached to the AGP card. Chances are the board will know it now has to boot from that. If not, I think the F2 key gets you into the bios where you should look for an item like primary graphics and set that to AGP.